PROFESSIONAL PAPER 103

BRA CHYCERA TOPS

A CERA TOPSIAN DINOSAUR FROM THE TWO MEDIC INE FORMATION OF MONTANA

NOTES ON ASSOCIATED FOSSIL REPTILES

BY .

CHA RLES W . G ILMORE

DEPA RTMENT OF THE INTERIOR

KL K FRA N IN . LANE , Secretary

‘ UN ITED STA TE S G E O LO G I CA L SURVEY

E GE s S ITH Director G OR 0 M ,

Professional Paper 103

BRA CHYCERA TOPS

A CERATOPSIAN DINOSAUR FR OM THE TWO MEDICINE FORMA TION OF MONTANA

WITH NOTES ON ASSOCIATED FOSSIL REP TILES

CHARLES W . G ILMORE

W A S H I N G T O N G O V E R N M E N T P R I N T I N G O F F I C E 1 9 1 7

CONTE NTS .

Introd uction

h of Two Medicine ormation b E ne i er Stratigrap y the f , y uge Steb ng

Fauna of the Two Medicine and related formations. Ceratopsidae

General features

Dermosupraoccipital

The vertebml column General features

Cervicals.

Dorsals.

Sacrum

Caudal vertebrae

The ribs

The chevrons.

Ossified tendons The shoulder girdle and fore limb

The pelvi c girdle and hind limb

Pubis

Metatarsus. Phalanges Restoration of Brachyceratops IV CON TE N TS .

Trachodontidae .

H au altis f ypaa oa rua pinusBrOwn.

n n Trachodo t ge . and sp . undet .

Trachodont gen. and sp . u ndet

Europlooephalussp

Chelonia .

ILLUSTRATIONS .

II . A B l n v r 30 mil r w ad andso Milk Ri e about esno th st of Cut Bank M nt. B Two Medicine forma , e , o , tion asx n Tw M cin Riv r M nt mati x n l e s o o edi e e o . 0 Tw M f k po ed , ; , o edicine or on ase posed o Mi

III . A Articulawd caudal vertebrae of Brach cerato smontanemisB rumof Bradt ceralo monta , y p ; , Sac y ps

' mnais C Sacral centra of B rach oerato smontalmwis. , , y p

I . l ti n of Bra z a monta V Ske etal restora o d yoer tops nensis. 3 . E f t FIG UR 1 . Generaliz ed section o he formationsof the Montaha group (Upper Cretaceous) in northwestern

' Skull of Bradt oerato smo mnmsla view y p nta , teral Skull of Brach oerato smontammissu rior view y p , pe Nasalsand nasal hemcoresof Bradcyceratopsmontanemis

Postfrontalsand prefrontalsof Braohyceratopsmontancnsis

Crosssection of dermosupraoccipital of Brachyoeratopsnwntanemis

Left exoccipital of Brachyceratopsmontanemis Left premaxillary Of Brachyoeratopsnwntanensis Left maxillary of Brachyoa 'atopsmontanemia

D Br a mon entary of achyoer tops tanemis.

Third upper tooth of BrachyceratOpsmontanmsis Unworn lower tooth of Brachyoeratopsnwntanemis Detached tooth of Brackyceratopsmontanerwis r Posterior cervical processof B achyceratopsnwntanemis. Anterior dorsal vertebra of Brachyceratopsmontanensis

Median dorsal vertebra of Brachyceratopsmontammis. Posterior dorsal vertebra of Brachyoeratopsnwntanemis

Centrumof dorsal vertebra of Brachyceratopsmontanenaw. Sacru mof Brachyceratopsmontanemiswith ilia in position Sacrumof Triceratopsprormswith ilia in position

A nterior caudal vertebra of Brackyceratopsnwntanerwis. Median caudal vertebra of Brachyceratopsmontanensis Distal caudal vertebrae of Brachyceratopsnwntanens

Dorsal ribsof Brachyceratopsnwntamnsis. Posterior dorsal rib of Brachyceratopsmontammis” Chevron of Brachyoeratopsnwntanensis

Left scapula of Brachyceratopsflwntanensis. Left ulna of BrachyceratOpsmontanmsis Proximal and distal porti onsof the radi usof Brachyccratopsnwntanensis Bonesprovisionally identified aspertaining to the forefoot of Brachyceratopsmntanensis Left iliumof Brachyceratopsmntanensis Left iliumof BrachyoeratOpsnwntammia CON TEN TS .

FIG U RE Right iliumof Triceratopsflabellatua Marsh Left pubisof Brachyoeratopsmontanemis Right ischiumof Brachyoeratopsmntanemis F emur of Brachyoeratopsmontammis

Left hind foot of Brachyccrawpsmontanensis Left hind foot of Brachyoeratopsmontanmsis

Left pubisof Hypaa ooaurusaltispinus? Brown A nterior caudal vertebra of Hypaa osaurusaltispinws? Brown Median caudal vertebra of Hypaa-osaurusaltispinusf Brown Right dentary of S tephanoaau msmarginatus? (Lambe)

Left ischi umof unidentified trachodont reptile . Right iliumof unidentified trachodont reptile

B HY AT P P D M RAC CER O S, A CERATO SIAN INOSAUR FRO THE TWO MEDICINE F F M WI H ORMATION O ONTANA, T NOTES ON ASSOCIATED FOSSIL

REPTILES.

1 By CHA R LES W . GIL MO RE .

INTRODUCTION.

The ssilson whic is a er is ase were c llec e me and m assisan fo h th p p b d o t d by y t t , F S ra er urin he summer Of 1 9 1 w ile w in un e h h U Mr . . t r t 3 r r t e ausicesOf n . J y , d g , h o k g d p t e ited S a esGe l ical Sur e on the Black ee ndian eser a i n in n r wesern M n ana T t t o og v y f t I R v t o , o th t o t . he specimenswere O btained fromexposuresof the TW O Medicine formation along Milk River near in T N W s w h un . 3 . 8 a u 0 e s Can ian ar 7 . . 3 mil n e e the ad bo d y , , R , bo t orth t of t town Of Cut

M n d al n TWO Medicine i er in T . 3 1 N . W . u 1 ssu w B an . an . 7 a 5 mile es k , o t , o g R v , R , bo t o th t of B er ra e remainswere un at se acesin 1 9 1 1 and 1 12 E Cut an . e e l 9 u ene Stebin er k V t b t fo d th p by g g , e he wasen a e in G e l ical Sur e w r and he wasthe firs n e a h l c li whil g g d o og v y o k , t to ot th t t e o a ties f din s im s e 2 h are good fields or fin g pec ensof fosil v rtebrates. Although t e present collection is smll it isOf c nsi era le scien ific in eres ecause it su lementsthe c llec i nsm a , o d b t t t b pp o t o ade in nei borin areas er in esi a rsand ecause it c n ainsa new enus Cera o si in gh g by oth v t g to , b o t g of t p a addition to other recogniz able specimenswhich afford evidence that considerably extendsthe es f er re esri e geologic and geographic rang O formsh etofo d c b d . The bedsfromwhich the collection wasmade constitute the upper part Of the Two Medi ine rma i n whic inclu esthe e ui alen Of the u i i er rma i n and sme e c fo t o , h d q v t J d th R v fo t o o Old r er us he f h B beds. The fossilif o bedsare also t equivalent of the upper part O t e elly River forma in ne rin ar an tion asfound ighbo g easof C ada. The auna Of the American udi i er rma i n al u i ersifie is er d f J th R v fo t o , tho gh d v d , v y ina e wn Man he ene and s un e o quately kno . y of t g ra pecieshave been fo d d n specimensso scant and fragmentary that it isalmost impossible to refer to themsubsequ ently discovered and more m eri e en i nsm M e f he Can Ge l a als. c c ll a e . am O a a er ec ec . t ical Sur e p f t t R t o t o d by L L b , d o og v y , B arnumBr wn the American Museum a ural Hisor r mthe Bell i e and by o , of of N t t y, f o y R v r rma i n al n Red Deer i er in Cana a we er a e lace is auna on a m re fo t o o g R v d , ho v , h v p d th f o solid basis. The purpose Of thispaper isto give ascomplete and detailed a description of the skeletal anatomy of B rachyceratopsmontanensisasthe material at hand will permit and to discuss rie in ssema ic r er er rmsre resen e secimensin the c llec i n ma e b fly, y t t o d , oth fo p t d by p o t o d in 1 9 13 . I take thisopportunity to expressmy thanksfor assistance rendered and for courtesies

' ex en e at man imes in the fiel and urin the re ara i n isre r t d d y t , both d d g p p t o of th po t, by T F se i Mr Eu ene sM. C . W . S an n and Knowltcn and e c all . Messr . . am ell . . R pb , t to , H , p y by g

Stebin er all Of the ni e S a esGe l ical Sur e . g , U t d t t o og v y

- STRATIG RAPIIY O F THE TWO MEDICINE FORMATION.

N E N By EUG E STE B I G ER .

A ll the vertebrate fossilsdescribed in thisr eport were collected froma single formation of r e a us a e w ic the name Two Me icine rma i n has een a lie Montana (Uppe Cr t ceo ) g , to h h d fo t o b pp d t f the lains recently by the United StatesGeological Survey . It occurshroughou t the part O p

1 A ssistant r f ossil re tiles nited StatesNational useum. curato o f p , U M 1 A J v l 4 1914 Stebinger, Eugene, W ashington cad . Sci . our., o . , p . 383, . 2 BRAC H YC ERA TOPS . region in Montana that liesat the east base of the LewisRange and the mountainsimmediate ly i s ll s ll n t t su . The rma n i we ex s in all the lar er ream a e sa d a man laces to he o th fo t o po ed g t v y , y p

ssr amsit iscar int intrica dlan s. See Pl. A . Th r ksar s along tho e t e ved o te ba d ( II , ) e oc e oft nd li h col re w ite to ra and reenis ra ein the re ailin in sand hie a g t o d , h g y g h g y b g p v g t t , are c fly cla cla sale and s san st ne . The san s nesare er irre ular in ickness innin y , y h , oft d o d to v y g th , th g

i in s rt disances and in lacesare sr n l cr ss- e e bein in art at l rap dly ho t , p t o g y o b dd d , g p east of s r i eolian origin. Thin bed of ed clay and thin nodular limestonesare occasonally found . The rma i n a era es ee in hicknessand is er uni rm in a earance hr u u fo t o v g f t t v y fo pp t o gho t , itsl 2 is except that owest 50 feet more sandy than itsupper part . Besi esa remarka le a un ance er ra r mains the ossilsin th Two i d b b d of v teb te e , f e Medic ne

rma i n inclu e bo in er e ra esand ts. Th in r ra a r in lan e . fo t o d th v t b t p e ve t b tes, cco d g to T W .

S ant n are rinci all res- wa er esan n t o , p p y f h t typ , d U io, ivi ams and Cam eloma the m V p , p are ost abundant

genera . Brackish- water formsare also frequently m g i s i un ese iall n the l wer an rt n. d am mnm fo d , p c y o dy po o Fossil “ m“ w sme it in c m le sec i ns r ood , o of o p te t o of t ee trunksas i i s mu as1 n esin am er i a un an . Th ch 8 ch d et , b d t e flora

so far collected isreported by F . H . Knowlton to be i i of Belly River age. The ev dence of rap d and irregu lar deposition afforded by the lithology of the forma i n o e er wi the resence a inosaur auna t o , t g th th p of d f ,

l n lants and res- water sellslea li l of a d p , of f h h , ves tt e doubt that the rocksasa whole are continental in

origin. the sra i ra the Two M i in Fortunately , t t g phy of ed c e formation and the formationsassociated with it can be il i re be use the sim lici th very easy dec phe d , ca of p ty of e mu msr nearly horiz ontal structure and the general excellence M d “ mm . of the exposuresthroughou t large areasof the Montana

group in northwestern Montana. The fact that the Two Medicine formationliesbelowone marine clayshale carrying a Pierre fauna and above another marine shale

carrying an upper Colorado fauna iswell established . 1 A ccording to recent work the section of the Montana u includin the N o Me icine rma i n asex gro p, g d fo t o , posed on Two Medicine River between itsmou th and amil s ffi ce c n ains ur li l ic unitsw ic F y po t o , o t fo tho og , h h n esi na e Vir elle sands ne N o Me icine have bee d g t d g to , d

rma i n Bear aw sale and Horsethief sandsone . fo t o , p h t

Frame 1 —Generauzed section of the formations0 ‘ "I" The C l ra sale carr in a c arac (See fig. o o do h , y g h an ’ ‘ ‘ teristic marine auna un erlieshisr u rma i ns flggmmfifigfimfi fifit f , d t g o p of fo t o mfjnfi g 0 mm“ cine formation from which most of “10 " and appearsinthe sectionat the mouth of N o Medicine

“ M M "" “1 't Wmmuwm' e e n ce River under bold cliffsof Virg ll sa dstone . Tra d Medi cine rma i n r e be exac l e ui alen northward the Virgelle sandstone and N o fo t o p ov to t y q v t ’ . D wsn reco n e the to the Belly River bedsasmapped by Dawson in southern Alberta a o g iz d i i in e bu no prominent sandstone at the base of the Belly River formation and descr bed t d tail t t is asal san s ne has een race er a lar e area asa separate formation. In Montana th b d to b t d ov g disinc ma a le in the western part of the State and haseverywhere been recogniz ed asa t t pp b ’ m e it im ssi le use Dawsn s esi na i n Bell i er for an the r c s unit . This ad po b to o d g t o y R v y of o k ’ n the name Two Medicine was ere re a e for the u er ar Dawsn s in Montana, a d th fo dopt d pp p t of o n the er an the rela i ns the u di i er rma i n the N o original formation. O oth h d , t o of J th R v fo t o to

I A Sci . J . vol. 4 . 383 1914 . W ashin ton cad . our Stebinger, Eugene, g , , p ,

- l ] e Pr ssRe t. for 1882 1884 . 1120 .1885. w G . M. Canada Geo . Surv y o re , p Da son, , g p F AU N A OF TH E TW O M EDICIN E A N D RELA TED F ORM A TION S . 3

Medicine formation became apparent on tracing the formationseastward toward the type area . n i r of the Judith River formationsin central Mo tana . The Judith River format on p ovesto be e i alen nl he u er ar e o Medicine rma i n which in itsen ire ise v qu v t to o y t pp p t of th Tw fo t o , t ty qui a len the u er art the E le he Cla e and the udi i er rma i nsc m ine . t to pp p of ag , t gg tt , J th R v fo t o o b d The stratigraphic positionsof the three principal horiz onsin the Two Medicine formation at which the fossilshere described were Obtained are indicated by arrowson the columnar sec r e m s ec e in 1 1 were e r e tion. (See fig. All the verteb at re ain coll t d 9 3 obtain d f omth upper al he rma i n so a the ase the verl in marine sale the Bear aw wasthe ms h f of t fo t o , th t b of o y g h , p , o t i s convenient datumfor fixing the stratigraphic postion of the fo sil localities. Thisupper part Me icine rma i n isver ssilifer us ne ra men s ein a un an hr u u of the Two d fo t o y fo o , bo f g t b g b d t t o gho t

- i the strata and no well marked z onal distribut on being apparent . For the sake of stratigraphic e riz nsat w ic ms the secimenswere c llec e are escri e el accuracy thre ho o h h o t of p o t d d b d b ow, e sri n ese ssilsis i e e without implying that th di t butio of th fo at all limted to th shoriz ons. Hori ‘ 1 w ic Bmch cerato smontanemisand H acrosaumsaltis nusl were c ec on . at i ll e z No , h h y p yp p o t d

. lies340 ee e w he se e ear awsale ase se n i er in . 37 . 8 W l t a th B x o Milk R v T N R , f t b o b of p h po d

e 1 on the slopesof Landslide Butte on the south dge of thistownship . In the N . } sec. 27 the beds at thishoriz on lie immediately above a z one of claysabou t 10 feet thick filled with minute

- se es n e se mentssee X X Pl. A a aren l mainl Uniosw ic r asa xcellen marker h ll frag ( , II , ) , pp t y y , h h v t m s H r a e b e be a e it r whic Brach cerato and ac osumsw re c llec . for the on d bov , f o h y p yp o ted This e ne can be race for ab u al a mile n r weswar a in w ere the river valle sh ll z o t d o t h f o th t d , to po t h y

l n war an ismar e r u u a un an ssil nes. ll he s c turnsabrupt y orth d , d k d th o gho t by b d t fo bo A t pe i

nsiswere un 1 1 milesn his see emto snwntane r l cali Pl. mensof Brachyc p fo d } o th of t o ty ( II ,

e en l weswar - di in edsat nearl he same eleva i n ere re a on the strike of th g t y t d pp g b , y t t o and th fo t

r xima el the same stra i ra ic si i n. riz ns2 and 3 at whic ma erial wascol app o t y t g ph po t o Ho o , h t 1 s e e n Two Medicine iver in T. 3 . 7 W . were fixe tra i ra icall m asurin l cted o R N R , d t g ph y by g

war r mthe ase the Bear awshale asex ose 6 milesto the wes. riz n 2 a down d f o b of p p d t Ho o , t w n en ifi e rac n O . 7955 U . S . N . M. wasc llec e on the su h si e hich a unid t d t hodo t (N , ) o t d o t d of s e sec. 1 5 ee Pl. II isa 4 0 ee e e e o e cine iver in th NE . B u 9 l w th B ar aw Tw M di R 4 ( , ) , bo t f t b o p c e s si e e r b he s riz n 3 hi iel a trac n on the t ri e in . e . shale . Ho o , w h y d d hodo t outh d of h v , ut t NE i e

. is44 ee wer e r l 3 s e s U . . l in a xima ee b wt e a 12 . S 5 e 5 el m (No 8058, N f t o , b g pp o t y 9 f t o h hale and therefore very near the center of the Two Medicine formation.

FAUNA OF THE TWO MEDICINE AND RELATED FORMATIONS .

V ra e ssilsare un hr u u the u er art the N O Medicine rma i n an erteb t fo fo d t o gho t pp p of fo t o , d nearly all of thembelong to the classReptilia. The great number of trachodontsfound appears s to indicate that these were the mo t abundant dinosaursof the epoch . Their remainsare dis se the er the r resen in the er alf the Two Me i tributed fromthe ba to v y top of bedsep t g upp h of d

ine rma i n asex sed In the l cali ies isi e In 19 13 al n Milk and Two Me icine ri ers. c fo t o , po o t v t d o g d v On each of the 1 5 daysspent in prospecting 8 to 14 specimenssufficiently complete to be recog s ainin the Trach n i ae were isc ered . Onl a few e e we er were niz ed aspert g to odo t d d ov y of th , ho v , warran c llec in and n ne were in ac u man un inthe E mn n perf ect enough to t o t g, o t t , tho gh y fo d d o to and Belly River areasin Canada and in the Lance formation of Wyoming and Montana were still articulated . n i ae the ra si ae were msa un an bu the al a z en Next to the Trachodo t d Ce top d o t b d t, t of h f do specimensfound only one (the type specimen of B rachyceratopsnwntanensis) isof scientific res the ersc nsisin ei er sin le nesor ra men sso adl wea ere as be inte t , oth o t g th of g bo of f g t b y th d to mm rs e r T e s w we er the exisence ere lar e e e th u . of little value . h y ho , ho v , t h of g b of g o p A rmre inosaurswere resen in ese l cali iesasin ica e the fin in the ermal o d d p t th o t , d t d by d g of d

mem er the Ank losauridae r isi nall re erre the enusEuro loce lwlus. platesof a b of y , p ov o y f d to g p p r us inosaursare c mm n but sele al remainsa ear be rare exce t Teeth of carnivo o d o o , k t pp to , p a ear r mthe scan e i ence a se eral small saurs w ich assingle bones. It would pp f o t v d th t v dino of h little isknown lived at thistime . 4 BRA C H YCER ATOPS .

Fra men s urtlesar len i ul but no c m le e se er b rv s - llsw e se ed . The e e g t of t ep t f , o p t h o oft sh ll d kin sa ear re mina e A fe ee . w h and sin le nes extinc cr c leswere d pp to p do t t t g bo of t o odi found , but nl two erte ral contra the l n - sn u e rh ncoce halian re ile Chamsosaurus o y v b of o g o t d y p pt p , whic isa an in sm r h bund t o e a easof the Belly River formation. sla e scalesand la es an i fises r a l re era le the enusL e isosteuswere I o t d p t of g o d h , p ob b y f b to g p , ere n her found h a d t e throughout the beds. The genera and speciesidentified fromthissmall collectionfromthe TW O Medicine formation are asfollows

Ceratopsidae Rhyncocephalia; Brach cerato smontanens ilmore is . a y p G Ch mpsosaurussp .

n s. na e Ce to sian en. a d d t. ra p , g p Chelonia : hodontidae Trac Basilemyssp .

H a rosaurusaltisinus? Brown. r tes yp c p Aspide e foveatus(Leidy) . hanosa usmar i t ? m e Step ur g na us(La b ) . Aspideretessp .

Trachodont en. and s. undet l , g p . Crocody idae

Trachodont en. and s. undet. Lei , g p dyosuchussp . Ankylosauridae : Pisces: l Europ ocephalussp . Lepisosteussp .

The er e ra e auna the N o Me icine rma i n asre resen e issm ec v t b t f of d fo t o , p t d by th all coll ti n al u mea er ser e asa asisfor cl se c m arisnswi rela e aunasacc r s o , tho gh too g to v b o o p o th t d f , o d with the stratigraphic evidence for the correlation of the upper part of the N o Medicine forma

- tion with the dinosaur bearing bedsof the Judith River and Belly River formations. Thisis shown not so much perhapsby identity of formsasby the primitive faciesof the fauna asa w le and als the similari in e ree e el men sme the rinci al re a ho , o by ty d g of d v op t of o of p p present tivesof the Dinosauria . The latter statement isespecially applicable to membersof the family i ae In r er ma e s e i r m b era s . k i assr n a li le cleare it a e well re iew rie C top d o d to th t o tt , y to v b fly r the development of the Ce atopsia . The earliest ceratopsiansknown were found in the Judith River and Belly River forma u ccurs in h n h tions. The gro p o also t e Edmo ton and in t e upper part of the Lance . In contrasting the ceratopsiansfromthese formationsthe chief differencesare found in the sruc ure the skull eseciall i the c m ara i e siz es the s r i al an nasal rn t t of , p y n o p t v of po to b t d ho cores s s and in the en or cl ed ruc ure the nuc al rill. In the udi i er Bell i er an op o t t of h f J th R v , y R v , d N o Me icine cera o siansthe nasal rn isusuall the lar er w ereasthe os r i al d t p ho y g , h p to b t horns m n a an sm imes n in In t e n c ra si s are s all rudime r d e wa . h a ce e an the osi e con , t y , o t t g L top opp t v rs Th sra e rill isa ll r r r i ns i nisuni e al . e ene ea ure a the ea lie ce a o sa but isre dit o f t t d f f t of t p , tained In the ance orms nl Torosaw' usand in lesser e ree Dicerato sall ers a in a L f o y by d g by p , oth h v g complete bony frill without fenestration. The earliest known Ceratopsia may be contrasted with those fromthe Lance formation as : 1 The in i i ualsare smaller 2 the nasal rn c re isusuall l r r t follows ( ) d v d , ( ) ho o y a ge than he r i al rn c res 3 the nuc al rill isim erfec l e el e 4 the ost r n posto b t ho o , ( ) h f p t y d v op d , ( ) p f o tal and rmosu raocci ital nesare less er ec l uni e 5 the suamosalsare s r er an he de p p bo p f t y t d , ( ) q ho t , d (6) t dentition isreduced . With all these primitive characteristicsthe single known Two Medicine genusBrushy i r i i i b si ceratopssin exact acco d . In add t on t may e a d that B rachyce mtopsmontanensisappears l i i a ' ' m m i f to have tsclosest affin ty with lllonocloni usdawsoni La be fro the Belly R ver o Canada . Pre i us 19 13 nl hree rec niz a le enera the Cera si ae MonocloniusCerato s v o to o y t og b g of top d ( , p , n r s ms er kn wn r mth u i i er B i er rma i ns in a Cent o au w e e and ell . S ce 1 1 d ) o f o J d th R v y R v fo t o 9 3 , we er the isc er newma erial hasm re an u le the num er escri e enera ho v , d ov y of t o th do b d b of d b d g , ’ ‘ Lambs avin esa lise the enera S t racosaums Chasmosaums Eocerato s and P rotero h g t b h d g y , f p ,

1 w 1 14 to B h o L L . On er n o Sin t o i m has h cerat e . M Eoc ato soanademia n v. ce his servat on smade 9 La bs re erred issecies rac s amb e . b a ( ) f p y p ( , , p , g , s N o 1 in C G S G sa x . 24 8 Ma 7 with remarkson other en r Cretaceoushorned d osaur : anad a eol. urve Mus. ull . 12 eo] . . g e aof y B , , , p , y ,

w C s rom h ll iv r ormati n of : O ttaw N turalist vol 1 - 116 Lame L . n s iesof erato ia t e e R e o A l erta a a . 27 . 09 . N A ne e usand c b , , g pe p f B y f b , , pp ,

s. 10- 12 1913 . pl , L O w n o tra ont ino om ll iv o mation of Al erta with mbe . n G rus lisa ne e usand seciesf ch d saur r the e R er r a La M. r osau notabi od , , yp , g p f B y f b , ‘ m . 155 ls. 1 20 Fe ar 1 14 scri tion of the skull oi Chasmosaumsb all: Ide 9 ru 9 . de p , p , p , , b y,

4 - mbe L . IL o . cit. On Eoc razo a canadcnsix . 1 25. La , , p ( e p , pp F A U N A OF TH E TW O M EDICIN E A N D RELA TED F ORM A TION S . 5

‘ 3 saums r mthe Bell i er Cana a and B rack cerato s avin een a e r mthe , f o y R v of d , y p h g b dd d f o Two Me in rm i n n n i n m eri l B rach dic e a Mo a a . Suffic e a a cemto swas aine ermi fo t o of t t t of y p obt d to p t ,

a skeletal restoration. (See Pl. IV .) Recent explorationsin the Edmonton formation show that these bedshave a char acteristic 3 ra sian auna re ar e Br wn as ein in erme ia e e ween a h ce top f , g d d by o b g t d t b t th t of t e Judith River and Belly River formationson the one hand and that of the Lance formation on the other

an wi affini iesnearer th se the rmer . The ac a a num er secimensr mthe h d , th t p of fo f t th t b of p f o l Edmonton of Canada are asyet undescribed rendersit impracticab e at thistime to make a una wi s h rma i cl se c m arisn is a e t e nsname . s ul b men i n o o p o of th f th tho of fo t o d It ho d e t o ed , w er a n ne the cera o sian enera the u i i er Bell i er or TW M ho ev , th t o of t p g of J d th R v , y R v , O edicine wn a e c n inue in ei r t formationsare kno to h v o t d to the he Edmonton or the Lance . sa e re i usl the rach n re ileswere the ms a un an di As t t d p v o y, t odo t pt o t b d t nosaursof the i r Bell i er and Two Me icine rma i nsand r n Judith R ve , y R v , d fo t o , ece t discoverieshave shown asdi i e in eir sru c ur as n themto be almost versfi d th t t e the co temporary ceratopsians. th enera S aurolo kusH ecrosaumsS te hanosaumsand Kritosa n v If e g p , yp , p , urusa d the fi e s ri e since 1 9 10 are inclu e no less an 1 enera and 2 s specie desc b d d d , th 5 g 5 peciesof North Ameri

can Trac n i ae ha e een escri e . The lis askn wn in 1 902 we er c nsisin 10 hodo t d v b d b d t o , ho v , o t g of 4 nera and 20 seciess ul be rea l re uce . a c er a re the re en i n nl ge p , ho d g t y d d H t h f vo d t t o of o y two nera CZaosaumsand Trachodon c nsi erin a the remainin ei were sn n ge , , o d g th t g ght y o ymsof w ul r sri h sn Trachodon. Claosaumshe o d e t ct to t e i gle speciesfromthe Niobrara formation of The findin m re er ec ma erial we er hass wn s r Kansas. g of o p f t t , ho v , ho that eve al of the species ’ formerly referred to Tmchodon represent distinct genera and that Hatcher sproposed reduction l ra wastoo radical. Of the severa gene established on good specimensit appearsvery likely that some will yet prove to be synonymsof earlier- described genera founded on fragment ary ma erial but hiscan be e ermine nl care ul c m arisn all h t , t d t d o y by f o p o of t e type specimens. Until such a revision ismade fewof the earlier described formswill be of use in correlation or u h le ic or er rel i n h in working o t t e phy t oth at o sof t e grou p . Hatcher wasprobably correct in in Claosaums the sin le secies r mthe iobrara a i n resric rm . isun r u na t t g to g p f o N fo t o It fo t te, r a hisO ini n a the enusTrachodon s ul inclu howeve , th t p o th t g ho d de speciesfrom the Ju dith i er the close the ance has ec me so wi el acce e erte ra e al n R v to of L b o d y pt d by v b t p eo tologists. h firs lace the e secies the enus Trac mira In t e t p , typ p of g ( hodon bilisLeidy) came fromthe “ udi i er rma i n and was un e on ina e u a e ma erial c nsisin secimens J th R v fo t o fo d d d q t t , ”o t g of p of te e enerall er mu c w rn and in a ra men ar c n i i n wi whi c it isw th g y v y h o f g t y o d t o , th h holly l i n i e r s impossible positive y to de t fy b tte pecimensdiscovered subsequently . That Hatcher “ later realiz ed thisfact isclearly shown by hisstatement that Although the trachodontsare asil disin uise eir tee r mthe er Din sauria ese e s udi i r i e y t g h d by th th f o oth o of th b d (J th R ve ) , t isscarcel ssi le i en i the ari ussecies is enusor the enera the amil y po b to”d t fy v o p of th g g of f y 5 fromthe teeth alone . E en u it ma e en uall be un a Trachodon canbe lace on a sound in v tho gh y v t y fo d th t p d foot g, “ isreasn for elie in a the enusisnot resen in the ance ass wn h l there o b v g th t g p t L , ho by t e ess num er ee in all the kn wn secimens r m the udi i er Bell i er and Two b of t th o p f o J th R v , y R v ,

Medicine formations. In e ance rac ntsse eral c m le e en aries whi c re in lu in Uni th L t hodo , v o p t d t of h a c ded the ted

Na i nal Museumc llec i nsthe r ws ee ar r m52 7 . All the udi i er States t o o t o , o of t th v y f o to 5 J th R v , B ll i er and Two Me icine trac n en ariesin the c llec i ns a e ewer r ws ar in e y R v , d hodo t d t o t o h v f o , v y g in number from39 to 46 . The same difference existsin the few maxillae available . It thus

1 O lim of i oro ino rom B i o mation of Al erta an w nusof Cerato f Lambe L . nthe fore a carn v usd saur the ell R ver r d a ne e sia rom , M b f y f b , g p

n m C iv ous Ottaw N i vol 1 1- 1 l on th in me t of so e re her or : a atural st . 27 3 14 me horiz on with remarks e te u taceous dinosaurs . 35 . the sa , g b , , pp , p ,

J 1914 . anuary , 1 inosaur f omthe usof on with no on H osa : Smithson COIL m C W A w to siand r r Cretaceo tana te ocr urus ian isc. Gil re . . ne cera e o , , p Upp M , yp M , — 1 - 1 . 1 1 4 vol. 63, No. 3, pp . 0, pis 2, 91 . 8 w A l A m i l l 14 rown arnumCretaceouscorrelationin Ne exico W omin ontana and l erta: Geo . Soc. er ca ui . vo . 25 . 374 19 . B , B , M , y g, M , b B , , p ,

4 J T softhe Trachodontidae Hadrosauridae Ci uridae arsh: Carne ie Mus. A nnalsvol. 1 . 385 1902. tchet . B . he enera and secie aosa Ha , , g p ( , ) M g , , p , — i J G l t f h J di R i : . S . ] . S rve 1 . s Geo u ull . 25 7 . 905 Stanton T . W . and Hatchet . B . eolo and a eon olo o t e u th ver ed 96 97 , , , , gy p gy b U y B , pp ,

l i newser . v . 41 . 658- 660 1915. G i more C . W . Onthe enusTrachodon: Sc ence ol l , , g , , , pp , 6 BRACH YCERA TOPS .

ms a the earliest kn wn rac n sli e the m re rimi i e cera o sians a e ewer see th t o t hodo t , k o p t v t p , h v f s ha nowit ma be sa el asserte a one the mar e hasesin the secializ a ion teeth , o t t y f y d th t of k d p p t of the membersof thisgroup in successive geologic peri odsisthe progressive increase in the number of teeth in the dent al magaz ines. n s as on s cimens r mthe u i i er rma i n and its The ge usTrachodon i b ed pe f o J d th R v fo t o , smaller number of teeth would indicate that it did not persist into the later formations. It m r r a Trac on s ul ei er be rea e asan in e ermina e enusor appearsto e, the efo e, th t hod ho d th t t d d t t g l a t n at the most should be restricted to Judith River species. Such restrictionwoul d e ve he La ce r wi u neric esi na i n unless a su the e specimensnow referred to T achodon tho t ge d g t o , by t dy of typ specimensone of the older generic termscan be revived . The geologic range of the Trachodontidae isconsiderably greater than that of the Ceratop si ae c mmencin in the i rara and c n inuin hr u the udi i er Bell i er Two d , o g N ob o t g t o gh J th R v , y R v , ns T isa ear li e the Cera si at M Edm n n an ce rma i . e ae the edicine, o to , d Lan fo t o h y d pp , k top d , close of the Lance. F ur enera H acrosaumsKritosaumsS te hanosaumsand Trachodon are now rec o g , yp , , p , , og n ccu rin in he udi i er and Bell i er rma ionsand two em H e ro iz ed aso r g t J th R v y R v fo t , of th , yp c scamsand S te hanosaums a e een i entifie in the collec i n r m the Two Me icine p , h v b d d t o f o d rma i n H acrosaums was escri e ri inall romthe E mnt n Al er a Cana a fo t o . yp d b d o g y f d o o of b t , d , Br wn ashe am a and Kritosaum frombedsin New Mexico described by o t Ojo Al o formtion. Br wn 3 asrecen l sh wn the eneric i en i the Gr osaurus am e r mthe Bell o h t y o g d t ty of yp of L b , f o y “ i er wit the Kritosaurus Br wn and the su esi n isma e ha as er re ilian R v , h of o , gg t o d t t oth pt a v a t am ma w ll b e remainsare of the prim ti e f cieshe Ojo Al o beds y e e of Judith Riv r age. 4 In a recent paper Brown hasshown that the family Trachodontidae may be divided na urall in two r u s se one a in a creste sull and a e isc ium and se t y to g o p , tho of h v g d k foot d h tho of t an a a n er ischiumwi isal ex ansi n the other lacking he crest d h ving sle d thout d t p o . Members ' the firs r u are so far kn wn nl r mthe Bell i er I"vo Me icine and Edmn n of t g o p o o y f o y R v , d , o to rma i nsw ereasre resen a i es the sec n rou are resen in rma ions w fo t o , h p t t v of o d g p p t all fo t as ell as inthe Judith River and the Lance. Little can be said at thistime of th e progressive changesthat have taken place in the ruc ure the Trac n i ae u it a ears a the en al ma az ine h st t of hodo t d , tho gh pp th t d t g of t e Lance trachodontscontainsa greater number of teeth than that of the trachodontsfromthe Judith

i er Bell i er and Two Me icine rma i ns. The resence ur i i sin the e h R v , y R v , d fo t o p of fo d g t p sof t e Judith River genusPteryopelyr would appear to indicate a foot more primitive than that of the three- te ed Lance trachodonts. Both the theropodousor flesh- eating dinosaursand the armored dinosaursare so little known that at present it isimpossible to make admuate comparison between the speciesof sn a i es he er o us r u w a differen oriz ns. e re e t e er re resen in a t h o R p t t v of th op do g o p , ho v , p t ll the i e in his a er and the su secimensnow at an will format onsdiscussd t p p , t dy of p h d doubtlessshow e r r i c an e a ha e a en lace in eir sele al sruc ure and th p og essve h g s. th t v t k p th k t t t thuswill be an aid in the future correlation of the separated formations. The rhyncocephalian reptile Champsosaumshasa wi der geologic range than any other of the n e me f l nian a ex inc re ilia rmsexce c urss o the che ener . emains Cha o t t pt fo , pt of o o o g R of mps scum a e een un in the udi i er Bell i er Two Medicine E mn n an e h v b fo d J th R v , y R v , , d o to , L c,

Puerc and F rt Uni n f rma i ns. Isli el a w en e er ma erial 13 n wn o, o o o t o It k y th t h b tt t k o the speci es will be un ar in successi e rma i nsbut hisac an not nowbe e e fo d to v y v fo t o , t f t c d t rmined . The crocodilesare represented in the Belly River formation by the single identifiable enusL eid osuchusa enus a c n inuesin the ance ass wn the e secimen g y , g th t o t to L , ho by typ p of L h i ha a a in eidyosuchusstembergii fromt e N c r County are in Wyom g . Isolated teeth and bones r Tw a i n are r n i n ifie e a n f omthe o Medicine formt o p ovisio ally de t d asp rt ining to thisge us.

1 A w h t saur H e r urua romhe Edmonton A r trac od on d o sof : A mM . v own m ne in c oaa t Cretaceou l erta usNat. Hist. ol. 2 Barnu . . ull 3 B , , , yp , f b B , ,

- pp . 395 406, 1913. m Cre O o A lamo edsof New exico with descri tionof th w K A mM r u sNat. . own arn The taceous e ne dinosaur ritosaurua: . u . Hist B , B , j b M , p

ull. vol . 28 . 257- 274 1910. B , , pp , 8 W r W r sitsor h M 4 J . G r alte Pa eocene J s N x : A mM t vo . 3 . S clair . an e l de o t e San uan a st. ull . l 3 . 303 1 1 in d an in . e . us. Na . Hi 9 , , g , , p B , . B , , p ,

4 mCretaceous- Eocene correlationinNew exico W om on A A m v 25 — 4 rown Barnu in tana lberta: Geol. Soc . ull . ol. . 355 380 191 . B , , M , y g, M , . B , , pp , smcnv nm' psM N TA N N SI GIL M c ro O E S ORE . 7

The turtlesare represented inthe collection made in 19 13 fromthe Two Medicine formation

nl two i en ifia le se imen One ese B asilem . i a c s. ss s in eres as vin its by o y d t b p of th , y p , of t t h g nea wi B nobi isHa m e e in NewMe B resaffini . l ro th s xico to w ic r wn hasa lie t ty th y, f b d h h o pp d the name O Alam husa aren l c rr ra in the in saurian e i ence on w i jo o , t pp t y o obo t g d o v d h ch the

Belly River formation wascorrelated with the bedsat Ojo A lamo . a n The fish Lepisosteushasa wide geologic r nge a d isvaluelessasa horiz on indicator. In c nclusi n it ma be rie sa ed ha the auna the Two Me icine rma i ns o o y b fly t t t t f of d fo t o , as n one small collec i n ison accoun its rimi i e a iesin a r represe ted by this t o , t of p t v f c cco d with the stratigraphic evidence for the correlation of these bedswith the dinosaur- bearing bedsof the T Judith River and Belly River formations. aken asa whole the faunasof the equivalent rma i nsare un u edl ancesrall rela e ose the ance for wi one exce i n fo t o do bt y t y t d to th of L , , th pt o , all the familiesrepresented in these older formationsare present also in the Lance. Notwithstanding the fact that certain of the earlier faunal listsseem to indicate that se eral enera and secies re iles ersise romBell i er ance ime the e i ence v g p of pt p t d f y R v to L t , v d that hasbeen gradually accumulating in recent yearsindicatesbeyond question that the fauna of the Judith River and Belly River formationsisdistinctly more primitive than the relate d rmsin the ance al u a few the mre ersisen essuc asChamsosaumsL eid fo L , tho gh of o p t t typ , h p , y o h and some ur le enera assr mone rma i n to the er. suc us, t t g , p f o fo t o oth

DESCRIPTIONS.

Family CB A TO P S IDA E Marsh.

BrachyceratopsmontanensisGilmore.

— - - — PlatesI III IV text r 2 9 11 26 28 39 41 47 . , , ; figu es , , ,

’

- — i mi ni n Mi . vol. o. . 2 lmore S thso a Coll . 63 N 3 1 10 ls. 1 1914 Brach cerato smntanems sc . y p G , , , , pp , p , — A era l n f a o . shown nasa sci consid b e ortio o ula k ll . 1 . o enusand e es disartic ted su N 795 U S N. ls Type f g p p ( , i g , i ref on ls ostfrontals ostorbitals remaxillariesmaxillarieslachr mal alisheno d and exocci ital. With this p r ta , p , p , p , , y , p , p a a ra mén ar ar of the fri a ri h den and a reden i vi onall associ ted f t t ll t tar tar . spro si y g y p , g y, p y — se . 16 T . 37 N. R . 8 W . Mil v B ndian rva on T n o M n l E . k kf loca it N c Ri er lac eet I Rese ti eto C unt o t. Type y , , , , , y, — o maxi o. 2 . . lvi a da stral and orti nsof the re llariesN 795 U N. sacrum arti ul cau l P at . R o S e s c ted ar ypes p p ( , , p , o th o No w sionall b n u sto e ti f the tail . 7953 U. S . N . with hich are rovi associated seriesof 50 verte rae co tin u p ( , p y b and ribstibia bula and artl articulated hind foot fromthe left side consistin of an astra ulus dorsal verte rae ; , fi , p y , g g . w m a a no n of e distal ro 4 eta rsalsand o a f a 1 No N . calcaneumand 2 tarsals th orti f fi th d 1 halan es . 7957 U . S . , , t p , p g ( , — o P aratype locality Same asthat f the type. — i s i i n m Generic and specific characters. Typ cally of small iz e . Skull with fac al port o uch abbreviated and deep vertically . Supraorbital horn coressmall and firmly united with post i asal rn c re u r w r mnasalslar e sli l recur e la erall c m resse orb tals. N ho o o tg o th f o , g , ght y v d , t y o p d , n ll m s wi m i s median cres i n i u i a e ian u ure . Frill c ara el h r and div ded lo g t d y by d t th o p t v y a p t , f s s n ir n emn r aren l o mall iz e and e el wi hin he me a el e . Bor e rill fenestrae app t y , t y t t di t d of f wi ara mar in i ns Den i i n c m are wi h Tricerato s scalloped but thout sep te g al ossificat o . t t o aso p d t p i i in t e s h fif ein si liumwi l e F e its h e t e e ial. r a x an e rea l re ce . e g t y du d v d g p , th b g v t g I th g t y p d d ' s r anterior blade that curvestrongly outwa d . — The specimens The specimensof B rachyce mtopson which the present description and restoration are based were found on Milk River within a small rectangular area of about 6 by 7 i h t e exce ion tw hin ee an hree series cau al er e rae e Pl. W h o d feet . (Se II , t pt of d f t t of d v t b , A 20 w sen ire and articula e wit the sacrum and 3 PI. . a one of which (No . 795 ; III , p ) t t d h i e wi h the el ic onesand em ra all the sele al artswere isassocia ed closely assoc at d t p v b f o , k t p d t and too closely intermingled to show to which individualsthey belonged . The proper association of the bonesof the different individualswasrendered still more n difficult by the f act that all the specimenswere of approximately the same siz e . Compariso of ss an nine isc ia s we a at leas five in i i ualswere resen and it portionsof no le th h ho d th t t d v d p t , isr i a skull ere were one or two m re. In the e the a cul te . isquite possible that th o typ ( d t d , No 795 1 ) the suturesinterlocked so perfectly asto leave no doubt that the assembled elements belonged to the same cranium. 8 BRAC H YCEBA TOPS .

O STEO LO G Y O F B RA C H YC ERA TO PS .

THE S K ULL .

General eatures— W en un the sull wasen irel isar icula e bu t th x ent f h fo d k t y d t t d , e e cell preservation of the bone and the absence of distortion rendered the assembling and correct ar icula i n he ca r mn c m a a i i t t o of t s tte ed ele e ts o p r t vely easy . Thisspec men isof the utmost im ortance in the ro er in er re a i n the cranial elementseseci s a he p p p t p t t o of , p ally of tho e p rtsof t a ia i o m cer topsn cran umthat are n wso ewhat in controversy. The the enusand seciesaswassate issm Thissa emen isru o far a e all. e s s typ of g p , t d , t t t t a lie the n wn secimensbu t it sh ul be a e a sme exten the small siz e pp d to k o p , o d dd d th t to o t of ese secimnsma b imma uri Th n s h a m an e e due . e e su ure t e sull scru d er e th p y to t ty op t of k , , v t brae al if in i i ua s l test y to the you th of the d v d l . The acial rti n the sull is rea l a re ia e asc m are wi a the cerato f po o of k g t y bb v t d , o p d th th t of p sians a i fi a of the Lance formt on. (See g. It isto thisshortening th t the generic name refers.

— - S f h mt smontonemisG re N 1 U . S . N One third nat iz e. teral view 4 B rac e mo . o. 795 . . ural s La m2. kull o c o il . Dent r From y p , M , a y intrill i iniraorbital oreman m inter mietal al l lachr mal mz maxillar a nasal oh nasal horn coresno anterior fenestra f ; , ; jug ; y ; y ; , ; , ; f, ; f , p p j , , , , 0 it or icle t f h rn re d reden reir tal m remaxil r o t h narial opening; , orb ; , oss on op o nasal o co ; p , p tary ; pf, p on ; p z , p la y ; p , postorbi al; po , post r e f f orbital homcore; r, ostral; , suture separating halveso nasal horn; sq, squamosal; so, sutural bord er on prefrontal or small supraorbital;

for uamsal st su ratem r l (case. as, sutural surfaces sq o ; f , p po a

arial enin asin er kn wn udi i er and Bell i er rmsiswe a The n op g, oth o J th R v y R v fo , ll forw rd and he nasal rn w ereasin the later and m re i l secializ e Tricerato s is e is under t ho , h o h gh y p d p th orific entirely posterior to that horn. The distance between the nasal and supraorbital hornsisex in l s r win lar el the s r ene nasal nesthe rea re and aft e el men ceed g y ho t , o g g y to ho t d bo , g t fo d v op t a o n the nasal orn and the rwar si i n er the r i of of the basl p rtio of h , fo d po t o ov o b ts the small brow horns. The exact pitch of the frill portion in relation to the anterior part of the skull can not be ur 2 i h lac in ac r a positively determined . Infig e t asbeen p ed co d nce with the evidence of articu lated skulls. A n entirely new phase of nasal horn development and one whi ch appearsto be unique among dinosaursappearsin the longitudinal separation of the horn core into two halvesby the a i a ears b an o i nasal su ture . The nasl horn tself pp to e outgr wth fromthe nasal bonesnstead of a i ri ina e r ma se ara e cen er ssifica i n asin the m re secializ e Tricer s h v ng o g t d f o p t t of o t o , o p d atop .

' ‘ 10 BRA CH YC EBA I OP S . ex ernal si e a narr e i a ural srface s fi 2 asfor he a ic a i sma w r c l su u o . w t r ul n the ll t d o v t t ( , g ) t t o of s ra r i ne ich ismissin Thiselemen w ul a e c m le e c i a u al w . the i ene r l p o b t bo , h g t o d h v o p t d th k d o b t border which proj ectsimmediately in front of the eye and whi ch formsso conspicu ousa feature f h e ia h r ri nd he re n a a i o t e c ratopsn skull. On t e u ppe poste or e of t p fro t l pointed pegl ke pro ee i n isrecei e in a c rres n in it in the an eri r r er the sr n al ussren j t o v d o po d g p t o bo d of po tf o t , th t gth r n a is a i n a i cuing the union of these two bones. The p efro t l j ust b rely n co t ct with the postorb tal i a at the base of the postorb t l horn core . — x ro P ostfrontals. The true e tent of the postf ntalsin the ceratopsian sku ll ishere correctly determined for the first time. A u thoritieshave heretofore considered the postfrontal asex tending fromthe median line outward and including all of that portion of the skull here desig s nated aspo tfrontal and postorbital. (S ee fig. In thisspecimen a longitudinal su ture j ust internal to the base of the supraorbital horn core dividesthe so- called postfrontal into two

B

E 4 —N d sal h mco f B rach cerato smontanemic T N 1 S N O ne- hali naturalsiz e A S w FI . na so . e . 795 . . . . GUR asalsan e re . o . ide vie B iron y p yp , U M , ; , t w f with th l f f r ti i f r n l no te i vie . c S contact e maxillar es ur ace o ar culat n o re ta an r or nasal nin or , urface or re ;f s o f o ; o e bony ossicle on p , p , p g; , f h i f f i f w top o orncore; p , anter or processo nasal; po, orifice or super or processeso premaxillaries; e, suture separating t o halvesof nasal horn. s distinct element . The inner portion all paleontologistsagree in calling the postfrontal ; the wi u u es r n o o o H e 1 ou ter appears tho t q tion to eprese t the p st rbital . V n uen in 19 12 regarded the portion forming the posterior boundary of the orbit in a skull of TriceratOpsprorsasasrepresent in t e w le the sorbi al bu t the wri er uesi nst e c rrec nessof is e ermina i n g h ho of po t t , t q t o h o t th d t t o T er s in the genus ric atOp . In Brach cerato sthe sr n al isa smew a irre ularl rian ular ne l n er y p po tf o t o h t g y t g bo , o g than wi e w ic uni es su ure on the medianline wi itsell w the si e si e Se d , h h t by t th f o of oppo t d . ( e fig . A nteriorly the combined postfrontalsterminate in a pointed proj ection interposed between o the deeply emarginate posterior b rdersof the prefrontals. Posteriorly and on either side of the r n ramen ese ne i ul su ur wi postf o tal fo th bo sart c ate by t e th the median element of the frill. A x rn l r er uni s r i toothed e te a bo d te with the posto b tal. Beginning between the horn coresthe me ian u er surfaces the ostfrontalsare an ularl e resse ra uall ee enin and d pp of p g y d p d , g d y d p g wi enin ransersel as e a r ac the s ron al oramen muc asin S t racosaums d g t v y th y pp o h po tf t f , h y

' 2 albertensisLambe .

l i ich von Beltrii e z ur K nntnsdesCerato sldenschildels: N u J 2 151 H uene Fr edr e i e esahrb 1912 and fi . 3 . . , , g p . , , B , g , p L A w enusand seciesofCerato i romth ll iv 2 N l 2 B 1 1 . me . . ne sa e e R er ormation f A l ta: O ttawa Naturalist vol 7 o. 9 . 9 La o er . 3 b , M g p p f B y f b , , , p , BBA CH YCEBA TOPS M ON TA N EN SIS GIL M ORE . 1 1

a i e re ron alsand ostfrontalsin Brach erawsisunusu al for in most The rel t on of th p f t p yc p , a r al isin er os be ween em e rela i n s wn in Brach cerato s dinosaurian crani the f ont t p ed t th , th t o ho y p b in un elsew ere so farasthe wri er isaware nl inS te osaumsamn the Din sauria and e g fo d h , t , o y g o g o e ili Von Huene ass wn in some Of the P ermi an R pt a. h ho rrec l the wri er belie es a the r n al in Tricerato s (co t y, t v ) th t f o t p hasbeen entirely exclu ded from the dorsal surface Of the skull.

‘ — i al i esris e s a l su ra P ostorbital. The postorb t g v e to th ml p orbital hom core and formsnearly one- half of the orbital b s to ishom whic issi ua ed on t e order. Po terior th , h t t h end t e b ne aresint a wi e ex extreme anterior , h o fl o d panded u c e ex ernall wi a cur e se portion m ch defle t d t y , th v d po t rior , — Freon: 5. R ight prefrontal oi B rachyccratopc b t e inner alf rmin a or i n of the u er b un ar order, h h fo g p t o o t o d y montanemie. Type. N .M. Three snat w i u ratem oral f ssa and t e u er alf a in an fourth ural siz e. Internal vie . 1 S de o of the sp p o h o t h h v g , p W W W ? “M m"“ W W II su u or ar i ula i nwi e s underlapping t ral edge f t c t o th th quamosal. sal o r i i na ; , o b tal border; pf, sde articulating The srai h in eri r ed e mee sthe u al whic ismissin with the right postfrontal; so. supraorbital t g t f o g t j g , h g m i “ " in th sspecimen. The thi ckened anterior border showsa sutural e e for uni n dg o with the missing su praorbital bone. On the median inferior surface isa shallowpit which recei esthe u er end Of the alis en i asit v o t ph o d , doesin S te osaurus Com s s T e to auru and ri c ratO s. See g , p , p ( als ale fi o p, g. Immediately above the orbit onthe anterior part of the osorbi al ere risesa low rn re w p t t th ho co , hose upper extremity isobtusely rounded longitu dinally see oh fi 2 but issa l ( p , g. ) h rp y pointed transversely . The ex ernalsur ace of t is rn isl e e in e a t f h ho p an , th t rn l

sron l c n ex wi antero- t g y o v , th the posterior diameter ea l ex gr t y ceeding the transverse. Itstotal height a e bov the orbit is31 millimeters. These hemcores appear to be ou tgrowthsfromthe postorbital bones unlessthey include a posterior supraorbital element

' such ashasrecently been found in the skull of S tego ‘ saums. The type specimen showsno trace of such an element bu t its ssible exis e , po tenc again raisesthe u esi n t e r er esi na i n rns q t o of h p op d g t o of these ho , which have been called successively postfrontal and

supraorbital horncores. If they are ou tgrowthsfrom e s rbi al b ne ashe r n th po to t o , t p ese t specimenappears in ica e os rbi al rn core w ul m r to d t , p to t ho o d be the o e

appropriate designation. — Dermosupraoccipita l. The frill isrepresented by

— the me ian elements r m two in i i uals. (Nos. Fi ann a Postmark and prefrontalsoi B mclrycempe mon d f o d v d

mie T e. No. 7951 8 N . One- hall natural siz e. taue . . . . 0 and 795 1 U. . . M. P r i ns eac r yp , U M 795 , S N ) o t o of h a e

A Su erior view interior view. 1 Pit for rece tionof e . p ; B, , p p g missin but the be er- reser e secimen is r vi ont a mal M notch between re rontalswhich receives g, tt p v d p p o hel chry ; , p f sterior endsoi nasals re rontal ost rontal (ora po ; pf . p f ; p] . p f sionally associated with the type asshown in figures men ostor ital order o ostlrontal so su raor ital : p b b ; p f , p ; , p b 2 and 3 . T isasscia i n we er isnl r visi nal h o t o , ho v , o y p o o border. in so far asit a lies the ac ual indi idual for pp to t v ,

g withou t question all the bonesbelon to the same kind of an animal .

1 ilmre C W l armored D sauria inthe nited StatesNational useumwith secial re eren th nussu G o . . Osteo o oi the ino ce to e e marise: , , gy U M , p f g m 8 N Mu w 33 1914 U at s. ull ...... B , p , 54025°— l 7 —2 1 2 BRA CH YCEBA TOP S .

1 3‘ s ra cci ital or inter arie al for asclearl s wn H a and Von B uene The dermo up o p p t , y ho by y " isuni e su ure wi the an eri r r i n the skull at the s it can not be the p arietal, t d by t th t o po t o of po t h m an ar the in er arie al issar l ri e exce at the seri r frontal foramen. T e edi p t of t p t h p y dg d pt po t o

x remi where it a ensin a inner r i nwi an emar ina e me ian r er. Be ween e t ty , fl tt to th po t o th g t d bo d t

h m i n b ar in cr sssec i n isrian ular . See fi . The su eri r sur ace the fenestrae t e ed a , o t o , t g ( g p o f i u din sw of thisridge forward of itsnarrowest part between the fenestrae presentslowlong t al ell h r Pr xi all ingsarranged one in front of t e othe . o m y the median portion isgreatly compressed trans in o a s r nec rwar w ic it a ain versely t ho t k , fo d of h h g widensinto a much depressed end that articulates laterally with the postfrontalsand with themforms the u pper boundariesOf the postfrontal foramen o fi Be ween ese two la eral rti nsthe (f , g. t th t po o medi an surface isdeeply concave and slopesdown ward to a heavy truncated border that in all prob i assu urall uni e wi the arie als s abil ty w t y t d th p t (p , h erato sat least the arie al was fi . InB rac c g y p , p t tir i en in the rsal asec and it is re en ely h dd do p t, p sumed that similar conditionsobtained in Tricera o sal u Von uene wasincline to re ar a t p , tho gh H d g d 7 1 ‘ ' g g mi small portion of the median part of the frill pos gnfhfiff ms fi 15 25? ew cla Pit for rece tionof outer end ofalishenoid bor vi . p . p p d. terior to the postfrontal fo ramen in that genusas dot in contact with the jugal; ptf .border in articulation with ein aneta‘l the ostfrontal o orbital bord er; so su rface for articulation b g p p ; , , ' ' of su raor ital one; s. order for suamosal articulation; st o d th l p b b q b q ] , The bone surr un rng e ll ll fenestrae IS wflu mntrib utmg mm“ mm°f the “upmmmmm er in but it ic ens war the la eral ree {ga v y th , th k to d t f ri r Pr im edgesand poste o ly . ox ally it remainsthin where it formsthe floor O f the supratemporal fossae but thickenstoward the su tural border for the su amsal s 9 The exac sa an x n the rill enesra can no ur q o ( q, fig . ) t h pe d e te t of f f t e t be acc ately e ermine r mthe a aila le secimensbu t i i ar n a e r d t d f o v b p , t isread ly app e t th t th y we e comparatively Th sur aces the rill are rela i h r r small . e f of f t vely smooth and lack t e amifying systemof vascula

r o es the la er cera o sians. T ere were no e occi ital neson the mar ins the rill g o v of t t p h p p bo g of f , bu t a seriesof prominenceson either side of the median emargination give the periphery a pecu liar scalloped effect much like that imparted by the separate ossi o r ficationsof the Tricerat psf ills. Laterally the median portion uniteswith the squamosal by a straight su tural edge that isdirected forward and inward toward the center of the sku ll" A triangul ar ou tward proj ection with an upper striated surface at the anterior termination of the squ amosal su ture ntsa sur ace a was erla e h s sals represe f th t ov pp d by t e articul ated qu amo pm,“ section or der.

2 s fi . A low sar ia nall irec e ri e a aren l ; q, g , h p , d go y d t d dg pp t y the steri r er a th su Th su am sa sare mdrcates l e amsal. e l N Thm fourthsmt mlsiw, po o ov p of q o q o M , u “ e l 0 mm missin bu t a ear asin er rimi i e cera o sians a e een I g pp , oth p t v t p , to h v b 222 fégfjftgggf short and broad . (See fig . 3 n — in the firs cr h ci ere u is Lachry url. S ce t des iption and illustrationsof t e spe esw p bl hed a or i n the le lac r mal has een rec niz e and it iss wn in the c rrec e rawin p t o of ft h y b og d , ho o t d d g of

the skull (fig . n the e secimen nl the r i al r er remainsbu iss wsthe r i to be m re I typ p o y o b t bo d , t th ho o b t o es nearly circular than wasindicated in the first restoration of the skull. It articulat with the

1 H a O . P . Onthe skull and the brainof Tricerato swith notesonthe brain casesof Imnodon and Me alosau rus: . 8 . N at. Mus. Proc. y, , p , o U ,

vol. 36, p . 97, 1909 . 2 nn n sidenschad ls: N rb — fi 4 an t sd Cerato e e osa s. 3 5 d 6 . Huene Friedrich von Beitrfi e z ur Ke i es u J h 1912 and 2 . 150 156 , , g p , B , pp , g , , ,

din saur romthe er Cretaceous0 1 ntana wit n n H r uru s: S mithsonian Misc. Coil . Gilmore C . W . A newcerato sian o o h ote o oc osa , , p f Upp M , yp , N vol . 63, o. 3, 1914 . BRA CH YCEBA TOP S M ON TA N EN SIS GIL M ORE . 1 3

r r er a s r lun e li e r ec i n w ic isrecei e in a prefrontal on the ou te bo d by ho t, b t, p g k p oj t o h h v d

u r eri r r er the re r n al . w ul be scarcel in c n ac if at pit on the o te ant o bo d of p f o t It o d y o t t, cim sh ws a the wi the su ra r i al ne whic ismissin in isse en. als all, th p o b t bo , h g th p It o o th t i a srian ular the seri r end ein eseciall eav where it a u tsa ains the supraorb t l i t g , po t o b g p y h y b g t T i th r mal postorbital at the base of the postorbital horn core. he forward extenson of e lach y

ismissing. — s en i the le si e is reser e but li e all her elemen s the ishenm. The ali A l p ph o d of ft d p v d , k ot t of I r r m se h sull wasdisar icul a e in issecimen. n u line it issu ian ula rese lin cl l t e k , t t d th p o t bt g , b g o y

o Th u er ex r mi has sm - finished r u n e homologouselement in the Tricerat psskull. e o t t e ty a ooth o d d

— m r n N - n v FIG . Der su raocci ital i r ri f B . . M. O hal atural siz e A rsal i w UR E 9 o o te a etal o rach cerato smontonemfs. O 7950 ne . Do e p p p y p , U f , ; n v n n v m l ve tral iew. c Bord ersthat united with the ostfro tals er ord ersthat u ited with the arietal ssurface for o erla ofsua osa . B , pi , p ;p , b p ; q, p q

end that isreceived in a pit on the ventral surface of the postorbital j ust posterior to the orbit at r the base of the horn core. Posteriorly it presentsa heavy su tu al border that u nited with the r h r i prootic . Itsinner portion ishollowed out and fo mst e wall of the po t on of the brain case

s As 24 1 . S . h h r r emi r in T tus . sulca . 6 U it ason a l est e ce e al e e. . th t odg b h ph (No , N itsinner rsal sur ace a su ural sur ace wi w ic the arie al uni e . Asin S te osaurus do f t f th h h p t t d g , Cam tosaurus Trachodon and Tricerato sthe alis en i in B rach cerato s rmsa r i n p , , p , ph o d y p fo po t o h s r m r Th r r of the anterior and inner boundariesof t e up ate po al fossa. e bo de forming the un ar O f the ramen ale is r en in the secimen bu t no u it is resen in a er ec bo d y fo ov b ok p , do bt p t p f t bone. 14 BRAC H YC EBA TOPS .

— Th n i Of a sm a ra mn is Exoccipital. e fro t sde o ewh t f g e tary bone that regarded asbeing the h i h wn exoccipital fromt e left sde of t e skull issho in figure 1 1 . It wasfound in the float at sme disance r mthe e secimen bu o t f o typ p , t it isquite possible that it pertainsto that

individual. The bone isflattened and platee and hasa broadly rounded external end or para occipital process that uniteswith the su amsal s fi Th n q o ( q, g. e in er end is cut off bli uel wi a o q y, th toothed su tural border which articulateswith the supra

cci i al so fi . h low r in a o p t ( , g Ont e e tern l an le Of isend seen b g th , est in posterior as c isa sm c nca pe t, ooth o ve surface whi ch representsthe u pper portion of the exoc cipital contribution to the boundary of ' the foramen magnum. The exoccipital ’ of Brachyceratops corroborates Huene s 1 determination that in the Ceratopsia the supraoccipital entersthe formation of the ramen ma num as it d esin man fo g , o y — m. T e. No.3“ moeu nocci itel of llronoclonfmcrw , mom 10. Der yp m p h r in saursand IS 11 0 O t e d o " 13 Gxcluded from N H isr One-ei hth natural siz e. Su e A mericanMuseumof atural to y . g p for articulation with suamosal e surface for i the ex cci i al as rmin riot view. m. Surface q ; pf , t, by o p t , dete ed by u mm“ ”mm" (“ m ) earlier authorities. The pedicel portion for articulation with the n h an eri r si e near basioccipital ismissing. O t e t o d , nd i issu urall r u ene and ia the internal e , t t y o gh d d g resen in a sur ace for the erla in onally ridged , p t g f ov pp g Of the r ic ro of the outwardly directed process p oot (p , asin Tricerato s Cam tosaurus and " S te o fig. p , p , g r si e near h wer b - er scum . On the posterio d , , gaelggout psfore isa sharp longitu dinal ridge which b low isri e at the reachingthe external end ; e th dg , Sutur l surface for rooticno sutural border for su reoc inner end the entrance to the foramen ovalisoccurs p , p , a n m i ital s e d which tsthe s mosal . c p . q, ee q ua sserratusMars as exactly asit doesin Triceratop h , “ h determined by H ay . T e greatest length of thisbone

is102 millimeters. — ma P remaxillaries. The pre xillariesOf Brachycer atopsare lessmassive and lack the lateral foramina

un in se Of Tricerato s. T e are c m resse fo d tho p h y o p d, thin bonesand are closely applied to one another along h n i the median line on t e a te r or half . Posteriorly they send backward and upward diverging processeswith expanded posterior extremitiesthat wedge between the m ar a h in a axill y nd t e descend g br nch Of the nasal. The median superior border of thispart of the pre maxillary istransversely rounded and formsthe lower un ar the an eri r narial enin no fi bo d y of t o op g ( , g. A ll the premaxillae in the collection were badly mu ti mm u p f m la e e re ssiliz a i n and n ne em a e eir i ffig ii mfifi fimmfi t d b fo fo t o , o of th h v th i i tho maxillar u rd er “nit m order mme wth y: m n i i m h - . B anterior asce d ng port onsce plete. T e best pre sal no anterior narial o enin n sur i with the na ; , p g , - ser e one (see fi . 12) exhrbrtsa in la eli e ascen in whith the m laps, v d g th p t k d g

l n Friedrich von B eitrii e z ur KenntnisdesCerato sidenschadels: NeuesJahrb . 1912 and 2 . 148- 150 fi . 2. Hue e, , g p , , B , pp , g

4 t notesn t rain f I onodonand Me a oeau . 8 . Nat s. P roc. Ha O . P . Onthe skull and the brainof Tricerato swi h o he b caseso u l rus: . Mu y, , p , o g U ,

l fi 1 . vol. 36, p . 101, p . 1 , g. 1 , 909 BRACH YCEBA TOPS M ON TA N EN SIS GIL M ORE . 1 5

r cess a iscl sel se the one - en the osi e si e the two risin th nasals p o th t o y oppo d to opp t d , g to e , a i in h ro e s fi 4 a h as Of h n where they re rece ved t e deep g ov ( ee g. ) t t e b e t e asal horn core. It seemsquite possible that the bony septumextendsdown farther into the narial O pening from h h n in ic in h r i s " the base of t e nasal bonesthan asbee d ated t e resto at on of the kull (fig. resem r a ms Monoclonius s noc bling in thisrespect S ty acosu ( ) phe ems(Cope) . T ere isno in ica i n an inter remaxillar n anelle asin Tricerato sand it a a h d t o of p y fo t , p , ppe rs m i r a l a the enin r u the re ax llariessee fi . 2 w ul if er ec b a in p ob b e th t op g th o gh p ( g ) o d , p f t , e th septumof bone extended fromthe narial border to the thickened anterior border over which the i The r sral esnot exten so far ac asin Tricerato sand h m r sral ar cula es. t e re axil o t t t o t do d b k p , p c n ri u esm o the su eri r r ers the a an i in a lary therefore o t b t ore t p o bo d of be k th t does th t genus. in eramina ar alswan in in hissecimen u h are c nsicu usin h Pal at e f e o t g t p , tho g they o p o t e pal atal surface of all Lance ceratopsians. Mar inad es— The maxillariesare

lar rian ular u line wi of irregu t g o t , th alveoli in the functional row for 20 — m c wer an in Tri cerato s teeth u h fe th p , imn which has40 alveoli. In the spec e unc i nal ee h a e allen out all the f t o t t h v f , but two or more germ teeth remain i i and give some dea of the r character. Posteriorly the maxillary isdivided into o ranc esan ascen in rocess a tw b h , d g p th t

icula wi the u al sfi . art tes th j g (j , g and an inferior horiz ontal branch that i n i isrelatively heav er tha n Triceratops. Onitssuperointemal side a longitu dinal roughened border isoverlapped by an anterior processfromthe pterygoid and i h a in isin contact wth t e pal t e. A nte riorly and su periorly the maxillary has an extended articulation with the pre m ar mz fi . Be ween the axill y (p , g t premaxillary and j ugal articulationsthe lachrymal and possibly the nasal were in contact with thisbone. (See fig . h n rornternal S l d a hOl‘ l on t e a te e — FI f maxillar f B montanemfe. T N U GURE 13. Le t y o rach cemto s y e. o. 7951 . S. y p p ,

sInwar m a - z ontal la e ex en eetin N .M. O ne halfnatural siz e. A E xternal view B internal view. a A nterior end p t t d d , g , ; , , ; ob alv lar r r d rami i inf r ital f ramen arti tin ‘ eo bo de ; ental fo na; rao b o s cula , f, ; i g Si milar p O] ect g plate frO n the Oppo , F surface for u al; osterior end ; m roove fer articulationwith remaxillary . l j g p, p p , g p o he mdi an lrn h srte maxrllary n t e e, t e rmin a r i n h in eri r si es t e rwar al a al sur ace asin Tricerato s. The an eri r f o d fo g po t o of fo d p t f , p t o sur ac is r i i h ex en e e e ra e a num er ramna rr ularl la . On half of t e t d d f p fo t d by b of fo , eg y p ced

h in rnal si e a cur e row 20 den al f ramina d fi . 13 B one to eac en al ro t e te d v d of t o ( f , g , ) , h d t g ove, l n h n a m extendsthe entire e gth of t e de t l agaz ine.

Th in ra r i al ramen fi . 13 ccu i a r xima l the sam osi i n asin th e f o b t fo (if, g ) o p es pp o te y e p t o e o m xi Th n a ri Tricerat ps a llary . e de t l se esoccupiesa longitudinal space of 155 millimeters. al i Internally the dent border sslightly concave fromend to end . — Th ro tral. The r sral ismissin r m the e b ut is n in a sli l smaller e s o t g f o typ , prese t ght y 2 N h s l . 7 5 U . S . S fi sec it r sem les e ra i i ua 9 . ee . In eneral a e t r ind v d l (No , ( g g p t b o t b h u x h d of Triceratops ut asa lessc rved anterior border. E ternally t e surfacesare pitted an w grooved and in life ere doubtlesscovered by a horny sheath . — Th i fo sm r siz isindistin u ish P . ed n n fi . xc r itsmuc redentary e pr e tary ( g e ept h alle e, g T i m h n a B h e s able fromthat of riceratops. It isto be dist ngu ished fro t e prede t ry of rac yc ratop dawsoni (Lambe) by the upward- tumed apex of the anterior end . B RAC H YCEBA TOPS .

— Dentar . The en ar issou ra uall narr win er i all ward the r n the y d t y t t, g d y o g v t c y to f o t, anterior end being especially depressed and unusu ally broad transversely and being nearly at h h d h x s right anglesto t e posterior portion. Near t e posterior en on t e e ternal surface a tou t w fi . 1 6 x h sc m ran r n i rocessc e en s el a t n al r r . It i e s rsel co o o d p ( , g ) t d l bove e de t bo de o pressd t ve y

bu wi ensan er seri rl wi a e rwar r c essasin er rimi i e cera sians. t d t opo t o y th hook d fo d p o , oth p t v top i s a low br a ri e exten s rwa a a u mdhei ht a n the u r si e the From t base , o d dg d fo rd t bo t i g lo g o te d of A h h dentary . bove and below t isridge t e ou ter surface re w treatsobliquely in ard . 1

iewe r ma e see fi . 1 7 B the en al r er is V d f o bov ( g , ) d t bo d straight b ut isobliquely placed in relation to the lower por — i n ha isit asses r m the inner seri r mar in t o t t , p f o po t o g to h h B h t e ou ter anterior marginof t e jaw. eneath t e coronoid processthere isa deep mandibular fossa which extendsfor — h ward abou t one third the length of t e dentary . On the

inner s h usual row of ramina d fi . 1 7 lea in ide ist e fo ( f , g ) d g

into the dental chamber. The exact number of alveoli can no be e rmine but the to seriesisrela i el s r er t d te d , oth t v y ho t an i n ei er Cera sor Tricerato s roba l not m re th th top p , p b y o 4 1 m m Flam “ m mBM ycm . 1 n . - an 7 en al r esbein rese N U sN M . O ne hali nat Paraty e. o. 7952 . . . p , th d t g oov g p t V ’W T — T sr resen e n a few erm $2;d Bias; eeth he dentition i ep t d by o ly g h c i n n a in allen ou t be re the aws teeth, t e fun t o al o esh v g f fo j Th h B d w r aws were entombed . at t e teeth of rachyceratopsin both u pper an lo e j are much T h maxi l e nd lessnumerou sthan those of riceratopsisindicated by a study of t e l a a dentary . B ch c the maxillae a fo 2 nd h en ar for 1 6 or 1 7 w ereas In ra y eratops h ve alveoli r 0 teeth a t e d t y , h in Tricerato sthe maxill ae a e m re an 40 and the en ar 30 or m re . p h v o th , d t y o In the left maxillary of the type specimen the third tooth fromthe front isretained in

h u . not ull eru e . n i position in t e alveol s (See fig . It isa young tooth and f y pt d A lo g d e i i esitsexternal sur ace in wo un u r i nsthe tu inal k el d v d f to t eq al po t o , Th h x larger being anterior. e point of t e crown posterior to the e ternal sbr en so a the c ntour h r wn o k wn but keel i ok th t o of t e c o isn t no , m inte h n isin Th doubtlessit is ore po d t a dicated in the drawing. e n srra h v i r er isfi el e e . On t nn a ea e l anter or bo d y t d e i er side is h y k e , e n o h more centrally plac d tha that n t e opposite side. The lower dentition isrepresented by the crownsof two germteeth

1 a ac e the den ar . T se rm e in bu t t fi . 7 e e e a e a ( , g ) tt h d to t y h g t th h v th i n o h in very high med a keel n t e ternal side. (See fig . The crown is in ed asin all unw rn cerato sian ee and its r a er po t , o p t th bo ders re s ra se oi the anteri r b r er bein finer an se h o ted , tho o o d g th tho of t e posteri r T of h border . he alveolar border t e dentary measu res1 06 millimeters and the maxill ar 1 55 mil imeters. A e ac e o su se r y l d t h d to th , ppo d to pe

ain to h is wn in fi u 2 . t t e typ e, sho g re 0 — F f S u ratemo a ossae The su ratem r s l al sa (at fi s. 2 3 p f p po fo f , g , ) 233 ?gmf m p r e } g m o en W i el be in asin all E mn on and B ell i er c sN - era o s U . p d y h d , d o t y R v t psmn . . . M. One half These large excavationsextend forward beneath the postorbital and n r s r n p , po terio e d , osr n al and la erall at i tsex1t enea the su ams Th i inferi r al. ese o rooessestbat underla p tf o t t y b th q o , p p u “ “mum" ree nes rmthe r asit were er the ssa he u b th bo fo oof ov fo , t pper oundaries h ssa exi ein rme eir sar r an in of t e fo t b g fo d by th h p ove h g g edges. The posterior floor of this ssa is rme the sm ne the dermosu raocci ital or fo fo d by ooth bo of p p interparietal. 1 H ay dissentsfromthe generally accepted determination that these lateral openingsin h c a sian ul n h su a em “ t e er top sk l represe t t e pr t poral fossae . H e says: I t isdifficult to under

B a 0 . P . O nthe skull and the rain of Tricerato swith notesonthe rain sesf [ n ca o ooden a d Mc u rus: . 8 . Nat. MusP y, , b p , b w galoca U . roc vol. 36, pp . 97, 98, 1909 .

1 8 smcny cnmror s. w ith the open stru cture of most other dinosaurian skulls. These modificationshave led to a rearran emen the e ements the cranium a un in n u g t of l of , th t til terpreted isasco f sing asit Th n h isu nusual . e bo esof t e skull become coossified early in life and thusstill further add to in h the difficul tiesof interpret g their relationsips.

' The r una e isc er the sull isu enile secimen B rach cerato aken in fo t t d ov y of k of th j v p of y ps, t c nnec i n wi the su ies Ha and Von H uene clearsu man th u in o t o th t d of y , p y of e do btful po ts a in th crania ana m a w re so uz z in o rel t g to e l to y th t e p l g t earlier investigators. It now appears a th re r n a sand ostfron w ic in h n rma n h th t e p f o t l p tals, h h t e o l reptilian cra iumare lateral to t e arietalsand r n als a e in the cera sian su us u wa and inw p f o t , h v top k ll p hed p rd ard above those m a n c l te c rin eir rsl as c . bo es, o p e ly ove g th do pe t That the postfrontalswere formerly separated isindicated in the Judith River and Belly

“ i er cera sians the n nc alescence eir seri r bor rswh c in h mm R v top by o o of th po t o de , i h t e later e bers the ance are alwa san l se . T is rin su the u si n the unc i n h of L ” y ky o d h b g p q e t o of f t o of t e “ “ ine ntanelle Mars the s r n al ramen h s r fon p al fo of h ; po tf o t”fo of Hatcher ; t e po tf ontal ” “ “ tanelle of Lull; the supratemporal fossae of H ay ; and the pseudopineal foramen of H u i i s in are now a ree a u n . All a h r e t isno mn e e t o t , I th k , g d th t i t a pineal fora e and that o n h c m ine su ra m it can n t represe t t e o b d p te poral fossae asinterpreted by H ay . The “ erm sr n al ramen is er a sthe ms a r ria e esi na i n for it isnot assu t po tf o t fo p h p o t pp op t d g t o , , g u 1 in an sense anal us the n e gested by L ll , y ogo to fo tan lle of human anatomy . Lull appearsto

‘ mm19 Frouar: 20 . m: Fro . Fro 18. — T montanensis T e. No. 1 . S . N . . Twice natural siz e . Externa v o m18. hird u r th of B rech cerato s . 795 l i w Fr m e too e . F n pp y p yp , U M ound i place inthe right maxillary . — N N n s nw rn l wer i mto montanemis. T e. o. 7951 . 8 . . . Twice atural iz e. Interna v FIG RE 19 . o o t th o B rach ce s l iew U U oo y p yp ;U M . Found in n place i the right dentary . ( See t, fig. — N s A E t montamsis. No. . 8 . . . Twice natural iz e. x l vi w F ront s20. Detached too h of B roch cmlo c terna e internal vi y p U M , ; B , ew.

w er in sa in a is enin ransmi snei er nervesnor bl be ri e esse s. ght, ho v , y g th t th op g t t th ood v l It a nl an enin not et r e ne in er w rdsthe c al isprob bly o y op g y oof d by bo ; oth o , o escence of the o frontalswi the dermosu raocci ital w ich c mmence ri r to Two Me icine im h p st th p p , h o d p o d t e ad n m x n in u not been perfected in La ce ti e e cept in an occasio al divid al . h —Th w m suremen s ac u d Measurementso t e skull. e ll in ea al an esima e w f fo o g t , t t t d , ere obtained fromthe type specimen:

Skull : reatest len th about G g , reatest breadth estimated G , Expanse of frontal region at base of browhorn cores Greatest width of nasals Length of interparietal along median line Height of nasal horn core above border of narial orifice Greate st width of postfrontals Greatest length of combined postfrontalsand prefrontals

Breadth between center of orbits.

Postorbital horn coresat base :

A nteroposterior diameter. Transverse diameter Length of postorbital fromfront to back

Horiz ontal diameter of orbit .

Nasal horn coresat base :

A nteroposterior diameters.

Transverse diameter . H eight above nasal orifice

l L ll R S . The Cerato sia: . S . G eo] . Surve Mon. 49 . 24 ootnote 1907. u . , , p U y , p , f , BRA OH YCERA TOPS M ON TA N EN SIS GILM ORE . 1 9

run “ 3 a

— General features The vertebral column of B rachyceratopsin front of the sacrumisknown nl r m issoc a e cen ra and neur r c esn n w ic w o y f o d i t d t al p o ess , o e of h h ere found in sequential

si i n. Presumabl we er it c nsistsasin Tricerato s 22 e br 8 in h po t o y, ho v , o p of v rte ae, t e neck and 1 h 4 in t e thoracic region. The remainder of the vertebral column isknown fromspecimen

NO . 7953 and c m risesthe sacrumand a c m le e ar icula e seriesOf cau a r o p o p t t t d d l ve tebrae, the fi m rst co plete tail of a ceratopsian dinosaur to be found . Thismaterial issupplemented by r Of o a ticul ated portions tw other tailsfrom the same fossil deposit . The vertebral formula ma be en a i i en asC 8 i D 14 2 S 6 C 50 y t t t vely g v , , , . r — Th rvic r n Ce vicals. e ce al egio isrepresented in the collection by a single neural process

(see fig. which evidently pertained to one of the posterior cervicaisand iscomplete except for the extremity of the spine. The arch isarticul ated with the centrumby heavy expanded

e icles. The neural canal islar e. The ia sesw i p d g d pophy , h ch are heavy and extend outward riz ntall romthe si e the arc are i u on th i ho o y f d of h , h gh p e sde of and somewhat anterior to the neural rocess. T e are a ene an er seri r b x p h y fl tt d t opo t o ly ut e panded dorsoventrally . The s i r z a esw r an h e d f h po ter o yg pophys ould ove h g t e n O t e centrum. The neural spine risesalmost er icall and ismuc narr wer re and aft an an the succe in v t y h o fo th y of ed g dorsals. ne the e ac e cen ra canbe a ribu e the cer ical re i n fo ne No of d t h d t tt t d to v g o , r no showa capitular n si e for the r i ul i n th ic T facet o the d a t c at o of e cerv al rib . In riceratopsit isknown froman articul ated presacral seriesthat thisfacet doesnot change its position on the centrumto the side of the arch until the third dorsal isreached . The processhasa greatest transverse di am eter of 88 millimeters. — Dorsals. The dorsal region isrepresented by 1 2 detached r c esand an e ual number cen ra romw ic r c p o ess q of t , f h h p o esses re resen in the an ri r me ian and s ri d rsa r i n p t g te o , d , po te or o l eg o s b en for u r i n fi 22 23 d Th e selec e l s s. an have t d il t at o ( g , , e c n ra s wn in the illusra i ns a e been arbi ra c e t ho t t o h v t rily pla ed , in so far astheir relationswith the associated dorsal processes n m m ‘ are c ncerne for n ne were un ar icula e . T e at leas mmti ii i o d , o fo d t t d h y t n fii, U M - S - N - W “ W “ Of h sa and r i n h n ive an i ea t e e ro s t e ce ra. g d h p p po t o of t d ? w Fi ure 22 s wsr n and si e iews a er e ra re ar e imtfimmi;ki i: g ho f o t d v of v t b g d d “mm“ m“ m 2 W ? W ? ' “ “ asbelonging to the anterior dorsal region. Probably it was fil z a h z a ma a m yg pop m' m W mpu h ur or fi ertebra for aswill be bser e the ara t e fo th fth v , , o v d , p phophysison the side of the arch isat the base of the transverse processand isa little removed A s Mo w he ia sisa c n i i n r e on the fif rsal Tricerato s. in no to ard t d pophy , o d t o obse v d th do of p ine A athaumasand m re eseciall Tricerato sthe ranserse r cessesincline u war cian , g , o p y p , t v p o p d ° h sesare l n wit a e ele 45 from t e horiz ontal. (See fig . The transverse proces o g h b v d d fo h u um h i Th in in ransersel wi a ackwar articul ar en r t e t bercul of t e r b . e sp e isth t v y , th b d ina i n itsu r ex remi nl si l excee in in ei the ranserse r cesses incl t o , ppe t ty o y l ght y d g h ght t v p o k nd mw when viewed laterally . The top appearsto be withou t transverse thic ening a rsso e hat

asin the an eri r rsalsOf the e secimen Tricerato scalicornisMars. The pointed , t o do typ p of p h s w u r c w en iewe r mthe r n isseen centrumprovi ionally associated ith thisne ral p o ess, h v d f o f o t ,

- Th to have the typical pear shaped ou tline of other ceratopsian dorsal centra . e diameter o b h same asin Tricerato sand asin a enusthe anteropOsteri rly appearsto e relatively t e p , th t g w A m w the cervical r cessthe neural articular endsare shallo ly biconcave. sco pared ith p o ar sar l incline and ex en canal isvery small. The anterior and posterior z ygapophyses e h p y d t d r r has rea es ranserse wi 100 well beyond the center of the vertebra. Thisve teb a a g t t t v dth of millimeters; greatest height of 130 millimeters; length of centrum32 millimeters; height of centrumat center 4 1 millimeters. 2 w si i n the ara o sison the inferi r The median dorsal (see fig. 3) sho sa higher po t o of p p phy o side of the transverse processand a broader spinousprocesswith a slight transverse thickening r d not so sar l incline u ward at itsupper extremity . The transverse processesa e shorter an h p y d p ' ‘ 20 BRA C H YC ERA I OPS .

m h iz n T c m o fro t e hor o tal. hey are also o pressed d rsoventrally and are wider anteroposteriorly

in the m an i r rss. Th a e o than ore ter o do al e z ygapophyses r also n t so highly inclined . All these changes are approxi mated in the Triceratopsback n Th v bo e. e greatesttranserse width of thisvertebra is99 millimeters; greatest height 132 millimeters; length of cen trum32 millimeters; height of centrum at center 40 milli

meters. The position in the verte bral column of the posterior rsa s do l ( ee fig. 24 ) may at once be recogniz ed by the horiz on tal plane of the anterior and steri r z a ses the po o yg pophy , by roa er and s r sin d b d horte p e, an the s r er weak r and by ho t , e , more depressed transverse — rior d sal ver o B m FIG RE . A nte or tebra i h s o. 8 . U 22 rac cerato onta N . . y ps nensi . N U . M ro Mo ms' reover t 0 ara O n - h natural also. A F ron w side vi p , h e al t vie ew. d Dia o h sisa neural canal p f , ; B , , p p y ; , ara o h sis; sspinous rocess; an suture etween centrumand rocess2 anterior p , p p p y , p , b p ; , pophysisiswell out On the ” h s's mm“ ” ‘s mwp y ‘ 1 mwphys' lower side of the transverse r cesst war the ia sial ar icul sur c for h b h p o o d d pophy t ar fa e t e ri . T e incisionsfor the prez yga o h sesand ostz a o h sesare muc ee er an in the rece in p p y p yg p p y h d p th p d g dorsals. The greatest transverse Width of thisvertebra is9 5 millimeters; greatest height 100 millimeters; greatest length of centrum32 milli meters reates ei oi cen rumat cen er 35 millim ; g t h ght t t eters. The su tural surfaces Of h t e centra (see fig. 25) nearly all agree in having two lateral pitsseparated by a short median trans erse v ridge.

mm25 mm24 Fro . FIG UR E 23. Fro . — FIG montancmis. N . . S N . O - siz . Lateral vi w. URE 23. Medlan dorsal verte ra of B rach cerato s O . . ne hal natural e e d Dia o b y p U M f , p ’ h sis s sino st tweefi centrumand ss2 anterior z a h sisz sterior z a h sis p y ;p , parapophy is;s, p usprocess;an, u ure be proce ; , yg pop y ; , po yg pop y . — FIGURE 24. Posterior dorsal verte ra of B rach cerato smontancmis. No. . 8 . N . . O ne- hal natural siz e. Lateral view: d Dia e b y p U M f , p ’ ‘ hysis; ara o hysis;ssinous rocess;an suture betweencentrumand rocess; 2 anterior z y a o hysis;z osterior z y a o hysis. p p , p p p , p , p , g p p , p g p p — p FIGUR E 25 . Centrumof dorsal verte ra of B rach cerato smontanmsis. No. . S . N . . O ne-haltnatural siz e. Lateral view. eu Suture b y p U M , for the spinousprocess.

Th n onl h c n T e last or sacrodorsal isreprese ted y by t e e tru min NO . 7953 . hough found h m h a s cimn it wasin s sci i n w i h m detac ed fro t e first sacral of th t pe e , clo e aso at o ith t in t e atrix and in an adult individual wou ld undoubtedly have been firmly coossified with the sacral as Th indicated by the su tural surface of itsposterior end . e centrumisslightly longer and more h A massive than any of the centra attribu ted to t e dorsal region. measurement taken at the BRA C H YCERA TOP S M O N TA N E N S IS GIL M ORE . 2 1

end s wsit to be wi er an hi . The la eral surfacesare a ene in a er ical irec i n ho d th gh t fl tt d v t d t o , h n w w w n A and t e ventral surfacesare broadly flatte ed ith t o shallo lo gitudinal grooves. heavy o h x a c n ri u s h u r the articular facet n t e posterior e tern l angle o t b te to t e sppo t of first sacral rib . The a en n rumis35 mill me ersand the rea es ei a en at the cen gre test l gth of ce t i t ; g t t h ght , t k ter, 3 1 is millimeters.

- sr a t n ra T sacru in the ara e NO . 7953 i e resen e ll he ce r i ns S acrum. h m e p typ , , p t d by t , po t o a s sa ral ri s of h s h s ri r er e r e and numer u e ac e c . S l t e neural procesesof t e po te o v t b , o d t h d b ( ee P . T s a e een c m r sse bu t a en all in all i a air B 0 ex fi . e e arts e l III , , ; t t g h p h v b o p d , t k g ve f y

— - FIG E moi B rach m montanemiswith ilia in sition. Parat N O urth natural s r UR 26. Sacru ws o e. o. ne fo iz e ri yce p p yp 7953, . Supe o

view. a A nterior end ;d dia o h sis;il ilium; osterior end ubic eduncle; ex asa ssessacral vertebrae Nos. 1 to 6 ac sacro , , p p y , p, p ; pp, p p , , , a h , ; ,

caudals; sr sacral ribs. ,

i good idea of the ch ef characteristicsof the sacrumin B rachyceratops. The centra are all su tur all uni e and in an a ul in i i ual w ul ou lessbe firml coossified asin er cerato y t d d t d v d o d d bt y , oth p a ara snin ar i ula c ra w a or si ns. The e ha e c e en ic the n eri six are re ar as p typ t t d t , of h h t g ded true s ral a h s r wo ac s nd t e po terio t astru e caudals. The remaining intermediate vertebra between tail and sacrumconstitu tesa modified cau dal that functionsto a certain extent asa sacral ca o s sa al and n ere re b e e i na e a croc u se fi . th f d g t d d ( , g The sacrumof the ara e inclu in the sacr rsal and the sacr cau al had ei h cen ra p typ , d g odo o d , g t t M o i with su tured articul ar ends. whereas on clon usand Triceratopshad ten such vertebrae. 22 BR ACH YCERA TOPS .

— - sh wi ili in siti n. N . O ne twel th nat l siz e. S u rior view «1 FIG R 27 . S ac i Tricerato s rorsus ar th a o o . ura e U E rumo p p M p M f p ,

r li m osterior end . fter at et . A nterio end ; 17 , i u ; p, p ( A H ch ) BBA CH YCEBA TO PS M ON TA N E N SIS GIL M ORE . 23

T is we er ma not c nsi u e a c nsan ifference e ween ese enera for it is uite h , ho v , y o t t t o t t d b t th g , q possible that in some specimensof B rachyceratopsone or more cau dale have acquired such an art cula i n us rin in the al num er u 10 asin kn wn cerat sian sacra. i t o , th b g g tot b p to , o op s ral ma b r z a nce the rea ranserse rea the cen rum The first ac y e ecogni ed t o by g t t v b dth of t , i a n n al surface and the in eri r si i n the seri r articular acetsfor the tsfl tte ed ve tr , f o po t o of po t o f l The sec n sacral cen rumisals isin uise r mall s n scral b s P . eco d a ri ( , , III , o d t o d t g h d f o r a th a ri r asc m ar wi h s ri r x r othersby the much greater b e dth of e nte o o p ed th t e po te o e t emity . Th n ra e r main sacralsare a u t e u al dimensi ns i er an wi e c nsric e ce t of th e ing of bo q o , h gh th d , o t ted me iall wi sli l a ene in eri r sur aces. d y , th ght y fl tt d f o f ’ s a ar s s cimn O . 072 U . S . . h we er s w cen ra e r a er an A econd pe e (N 8 , N o v , ho t th t b o d th inal r i n o ir eri r sur c high and that have a shallowlongitu d dep esso n the inf o faces. The differen es a r a due to crusin . The firs ree er ebrae Of the sacral r i n w ic re in all p ob bility h g t th v t eg o , h h a r ar l avi er an an a su c e m Th sa ra sare lu th sc rsal e eci e e ce e . e c l ri inc de e odo , d d d y h th y th t d th b

b ra - borne jointly by all the centra. The first ri joinsthe cent by well developed facetson the su eri r serior ex ernal an le the rssacral and on the su eri r an eri r ex ernal p o , po t , t g of do o p o , t o , t angle of the first sacral. The second and strongest sacral rib of the seriesarticul atesjointly wi th and s n rs low wn on the si es the cen ra th in eri r sur a th e first eco d do als do d of t , e f o f ce of the rib ein on a le el wi the en ral surface the sacrals. See Pl. The su cceedin ri s b g v th v t of ( III , g b articulate with facetsthat are bu t little belowthe level of the floor of the neural canal .

on i u inall the sacrumissr n l arc e see Pl. B o in r a is L g t d y t o g y h d ( III, ) , th ugh all p ob bility th

as - hing h been much exaggerated in thisspecimen by post mortemcauses. The fewspinousprocessesare exceedingly short thin platesof bone with little transverse thickening of their su perior extremities. That these were united into a bony plate isindicated a s a a r s an er ivi u . 2 S w e c e cral ces el n in to in al 7 U. . . ic by d t h d p o b o g g oth d d (No 80 , N h h showssu tural edgesfore and aft that continu e to the top of the spine. The same condition pre a son h s a il t e ine the fi sacral see Pl. B so it w ul a r hat his la ma a v p of fth ( III , ) , o d ppe t t p te y h ve n c n inu usr m ee mthe firs the fi uc asit isin Tricerato s. Th rela i s b o t o f o t to fth, h p e t ve hortness of the spinesin B rachyceratopswould at once distinguish itssacrumfromthat of the former genus. AsIn Triceratopsthe spinal cord appearsto have been only slightly enlarged in the ante rior sacral region. The diapophysesare comparatively weak and are given off on a horiz ontal

l n rom h ar s ir c rwar . a e t e neural c eswit in end e e See fi . T ir inf r p f h , h th d t d fo d ( g he erio bordersextend obliquely downward and inward and p resent a narrowsu tural edge for articula i n wi th u er a inner b r ers th sacral ri sw ic e rla su r l r t o th e pp nd o d of e b , h h th y ove p pe ior y . Nea lv all the rans rs r c esare missin bu t ir int ri in ass wn th r sur t ve e p o ess g, the po of o g , ho by e b oken

acesisin ica e in fi ur 26 arallel lin . f , d t d g e by p dotted es Though many sacral ribswere found none were articul ated and a description of themwoul d add li le th si i k o h tt to e po t ve n wledge of the structure of t e sacrum.

M sur ts n mll o a o sacral ae ea emen i i imeters centr vertebr . , , f f

Great length Greatest transverse diamete r : A nterior end

‘ — Candal vertebrae For the first time since the discovery O f ceratopsian dinosaursa complete ca s sa a a f r . u dal eriesof 50 vertebrae (paratype NO . 7953) i v il ble o stu dy The rea r um r w r un a cula e and suc islacemnt asxis wasso sli g te n be e e fo d rti t d , h d p e e ted ght that there can be no question that they represent a consecu tive series. Forty- six of themare re resente in Pla e A the remainin ur ein a ac e the ma rix to the sacrum. p d t III , , g fo b g tt h d by t

' (See Pl. IV .) BRA C H YC ERA TOP S .

sl r a a sa Th cen rum h firsor sacr cau al se Pl . 0 i n e h n wi e nd ha n artic e t of t e t o d ( , III , ) o g t d u for ar a of h lassa ra b Th lar facet on itssuperoantero lateral angle the ticul tion t e t c l ri . e neural arc al u o rl reser e indica es a the sine was isinc romthe sines rwar h , tho gh p o y p v d , t th t p d t t f p fo d r T a r r and s ri r z a of it. It had a decidedly b ackwa d inclination. he nte io po te o yg pophysesare s sa ra r rae Th als iff r n ia not c al ce a in all rece in c l e e . e ia seso o d e e t ted , o es d , p d g v t b d pophy n the first and second cau dalsare given O ff fromthe sidesof the arch well belowthe z ygapophyses h r su r bu ha th r cau al is elow a s a v t e neur cen al u e t on e u u ur . bu t bo e o t t , t t fo th d b th t t e The l s a l a i r a i s r centrumof the thi rd cau da iso b d y crushed th t t givesa poo ide of t p oportions. The we er s wsthe sine to be narr wer an er seri rl an it isin th firs and arch , ho v , ho p o , t opo t o y , th e t au dalsand the ia sisissmew a l wer on the si e of th arc an i sn h second c , d pophy o h t o d e h th t i i t e

first cau dal . The hir and ur caudalsare re resente the cen ra nl w ic like all a l w t d fo th p d by t o y , h h , th t fol o , are sho rt and have slightly biconcave endsand a transverse width that usually exceedsboth h the longitudinal and t e vertical diameters. s sn on h fi 2 Th Transerse r cesesare re e t e rs 5 er e rae . e an i r n x v p o p t t v t b ter o o es, e cept i l the firstwo or hree are l n and a ene and a e ea ex an e possb y t t , o g fl tt d h v h vy p d d articular ends w h c n u m n h d h fi that unite abou t equally ith t e e tr a d t e pe iclesof t e arch . (See g . These

F IG URE 28 . FIGURR 29 . FIG UR E 30 .

— - siz . F nt n i v ei h of montanemis. Parat . No. . S . N . . O ne hal natural e ro FIGUR E 28 . A ter or caudal erte ra th B rach cerato s e 7953 b ( g ) y p yp , U M f

view. c Centrum; a neural canal; a sine; t transverse rocess; 2 anterior z y a o hysis. , , , p , p , g p p

— - si . F nt view. FIG R i f B m sis Parat . N o. 79 . S . N . . O ne hal natural z e ro U E 29 . ed an caudal verte ra o rach cerato s ontancn . e 53 M b y p yp , U M f ’ c Centrum; sneural sine; su neurocentral suture t transverse rocess; z anterior z y a o h sisz osterior z y a o hysis. , , p , ; , p , g p p y ; , p g p p

— - s F nt view m N N na iz e. ro . FIGUR E 30 . Distal caudal verte rae of B rach ccrato s oatanemis. P arat e. o. 7953 . S . . . O ne half tural b y p yp , U M

A Twent - third twent -sixth . c Centrumssine 2 anterior z a o h sis. , y ; B , y , ; , p ; , yg p p y

h n irel gradually shorten posteriorly . In the twentieth centrum t e transverse isunited e t y wi h the cen rumand a l c u ur r i u l i n is i u in he nine een t t l tra e of st al a t c at o obl terated , tho gh t t th si nd n w h h it i svi ble a slightly i contact ith t e pedicle of t e arch . Th n ur c hrou u h u n ow Th c m r ss sines e e al ar hest gho t t e ca dal regio are l . e short o p e ed p of

h n eri r caud swi rans rsl ex an u er ex mi i ssee Pl. A raduall t e a t o al th t ve e y p ded pp tre t e ( III , ) g v narrow and become smaller and in the midcau dal region show no thickening of their u pper

ends. (See fig .

The anterior z ygapophysesare finger- like and extend forward with articular facesthat c u wa nd w fi Th fa e p rd a in ard . (See g . e posterior z ygapophysesare well up on the posterior h h border of t e spine and overhang t e endsof the centra . F unctional z ygapophysespersist wn h i h h h do onto t e d stal fourth of t e tail. In t e distal cau dals(fig . 30) t e neural processesare resen on the sec n the las but are wi u inesals the rocessesinstea ccu in p t o d to t, tho t sp ; o p , d of o py g the mi le the cen rum a e si e eir si i n rwar owar the an eri r nd asin dd of t , h v h ft d th po t o fo d t d t o e , T S tegosaurus. hese most distal caudaisalso have convex distal extremitiesand concave proxi u a w mal artic l r endsand are ithou t chevron facets. The anterior caudalsasfar back asthe thirty- ninth caudal fromthe sacrumhave O blique chevron facetson the posterior endsof the cen ra and ma a e had emnearl the i h ai in S o Th i h t t e l as t au r . e t y h v th y to p of t , eg s us t p of t e ail isc m se ree coossified cen ra the final one ein ar l m e an a r roun t o po d of th t , b g h d y or th sho t , ded

obtusely pointed ossicle.

26 BRAC H YCEBA TOPS .

are m re curve romend end wi an u war inc ina i n i u ro d o d f to , th p d l t o of the cap t lar p cessan a

re uce tubercular ace . The seri r ri ssee fi . 3 1 D ar slen r and s wi d d f t po t o b ( g , ) e de er traighter, th u a capitular processb t little angulated mrelation to the shaft . The capitulumand tuberculum are not so far rem e romone an er asin mre an eri r ribs isb in due h n ov d f oth o t o , th e g to t e shifti g h of the facetson t e dorsal vertebrae. In figure 32 isshown osmall curved bone that isdoubt h si u 32 ull re ar e asre resen in t e as rsal rib . It hasa n e cu e ic lar a a fi . f y g d d p t g l t do gl pp d art f ce ( , g ) onits r xim ex remi and if c rrec l i en ifie it r a cur e wn r mthe di o h p o al t ty , o t y d t d p ob bly v d do f o ap p y sison the insi e the iliumwi w ich it was ub lessin c ntact asinS te oaaum Thescelo d of , th h do t o , g , d m mumsan resuma l an her in saurs. , p b y y ot d o

Tn 0 8 1 7 3 0 3 8 .

No in u es e r nsromthe an eri r mi dle and seri r the ai In . 7953 cl d ch v o f t o , d , po t o partsof t l. the an eri r or n e are l n er an the sines the erte rae wi whic e ar icula e t o p tio th y o g th p of v b th h th y t t , bu t posteriorly they appear to reduce more rapidly than the

. sin us rocesses. T rou ut the series e a e the a, p o p h gho th y h v usu Y sa e u a few of th eri r nes he al h p , tho gh e ant o o have t ar icul r en sin c ntac on he median line usbri in t a d o t t , th dg g w n s M e we er he cle e ee the ranc e . re os ri rl t ft b t b h o p t o y, ho v ,

all have these endsseparate. The great length of the upper branchesascompared with the extremely short onesof the distal portion servesto isin u s the evr ns Brach/ cerato sr m se of er mount: 33. i c FIGURE as. d t g h h o of y p f o tho oth

escri e in saurs. The articula in ace sare c nfine h e“ : d b d d o t g f t o d to

U sN . 11 . O ne m m . No. . . he s ri r e e l mew a u war in he t po te o fac , though th y ook so h t p d t W “ ”m m” m “ an eri r cau al re i n bu t in the me ian and isal or i ns 233 t o d g o , d d t p t o e n m t m w h m w-m m o m m p of the tail they are more on the proximal face. The free h ° M end is lun tnmated h series The s is l c hrou u t e . af fm gm821 TQJQJ M b t y t gho t h t rounded in the anterior membersand issomewhat flattened m i and transversely in the ed an posterior chevrons. All are unusually straight and none have n s An ante e n m 4 e ee e . ri h vro eas 4 expand d fr d or c ures millimetersin length . A number of small bonesfound in the matrix surrounding the anterior ' portion of the tail

. 7 3 a e a a ene un e i ul ace er similar se the an eri r of No 95 h v fl tt d , ro d d art c ar f t v y to tho of t o

evrons he si e end bein sli l ex an e in the same lane. See fi . The ch , t oppo t g ght y p d d p ( g ea urved r mend end w at firs u ese mi be au al shaft isalso gr tly c f o to . It as t tho ght th ght c d ribsbu t the absence articular en son the ranserse r cessesthe true cau al ri sin is , of d t v p o ( d b th secimen esnot ada t itself isex lana i n and the nl al erna i e a su ess p ) do p to th p t o , o y t t v th t gg t e are evr n bon he wo an es ein se ara a eir ree ex remi ies i el is a c est t r c e t . tsf th t th y h o , b h b g p t th f t t Su n i i n isunkn wn in an re ile li in or ex inc and it is uite r ba le a is ch a co d t o o y pt v g t t, q p o b th t th

explanation isincorrect. - m s oasnn n emoir .

ns t P B we e un e ma rix n o si es e Ossifi ed ten l. r a ac al th do ( , III , ) fo d tt h d by t o g b th d of T a ese ossi ionswere e neural spinesof the sacrumin the paratype No . 7953 . h t th ficat also presnt on the anterior portionsof the tail isindicated by a fewfragmentsstill attached to the verte b er men ese en nswere un in the s ma rix immedi rae by matrix. Num ousfrag tsof th t do fo d oft t a el surroun in the ail and ub less e als ex en e rwar al n the orsal re i n t y d g t , do t th y o t d d fo d o g d g o , T e e slen er r un e r li e ossifications a era in a u 2 milli asin ri cerato s. ar T p h y d , o d d , od k , v g g bo t metersin diameter. m: r n enem asGmmx m r e mm.

— The m le sa ula Brach cerato sisas et un n wn bu t ra men ar S capula . co p te c p of y p y k o , f g t y portionsof two bonesof paratype No 7958 su pplement one another sufficiently to give a very

r r i ns See fi . 4 accurate conception of itsgeneral shape and p opo t o . ( g 3 . The scapula 1slong and narrow and issomewhat bent longitudinally to better conformto

The ar end 1s ea and hasa cu e sur ace fi . the curve of the thoracic cavity . articul h vy pp d f (g , g BBA CH YCEBA TO PS M ON TA N EN SIS G IL M ORE . 27

e T e e u e n nd miss . 34) for the articulation of the humrus. h thinn r pp r portio of thise is ing The vertical breadth of the shaft decreasesto itsmid length and again gradually expandsto

- e x T e x m r un e the squ arely cut off u pp r e tremity . he lower border on th pro i al half isb oadly ro d d

‘ — m N N O - t sca ula of B ch mto e ontana ms. o. 7958 . S . . . ne half natural siz e. External view. G id cavit . The G E 34. Lef m c leno FI UR p y p , U M 9, y

in a m si made romtwo onestheir overla ein indicated the dotted line. draw g isco po te f b , p b g by

u a ins war the u er end a sar e e The u er end iswi u rans bu t grad lly th to d pp to h p dg . pp tho t t e i en A ea un e ri e ex en su war u he u er surface ia nall r m v rse th ck ing . h vy ro d d dg t d p d o t o t d go y f o he seri r r er the len i cavi the u er an eri r r er t po t o bo d of g o d ty to pp t o bo d , e n in es e m in whenc it co t u backward asa thi ck ning of this arg . In gen ral r r i nsand u line the sca ula Brack ce mto sal u less e p opo t o o t p of y p , tho gh an al the siz e er cl sel resem lesthe sca ula Momclonius th h f , v y o y b p of wsoni as esri e and ure L sl is e isin i e da d c b d fig d by amb . It to b d t gu sh d 2 fromthe scapula of Triceratopsasfigured by Hatcher by itslack of an u pward expansion of the anterior u pper border of the blade and by the lessprominent development and more diagonal direction of the ridge on e e s th xternal ur face . A e h t presnt t e coracoid and humerusare unknown. U — The is se er u s T lna . ulna c ur m c maller ricera , of o , v y h than in to sbu t is erwise similar ein ea a e and bu t li le ex e p oth , b g h vy bov tt pand d d T n on the distal en . he olecrano processismassive and isproduced far a e the main ar icula in sur ace fo he h e T e s bov t t g f r t umrus. h haft ismuc a ene an er seri rl its seri r si e ein sall w h fl tt d t opo t o y , po t o d b g h o ly c nca e ransersel hr u u the rea er ar its en e o v t v y t o gho t g t p t of l gth . Th an eri r ace the isal rti n is r a l r un e ransersel bu t o f of d t po o b o d y o d d t v y t, more r ximall c an es a eci e nca e sur ce o he e e n p o y, h g to d d d co v fa f r t r c ptio e un e e h a T of th ro d d h ad of t e r dius. he distal articular end issmooth and extendsconsiderably u pward on the posterior side and isnot visible r m he r n See f o t f o t . ( fig. The u line the lecran n was rawn r m a sec n secimen o t of o o d f o o d p , and itssa e iscorrec . The rea eslen the e ulna see fi h p t g t t gth of l ft ( g. 35) esma 2 m is ti ted at abou t 1 3 milli eters. — R adius The radiusismore slender than the ulna and hasex en e en s w ic the isal isthe ea ier The r ximal end is p d d d , of h h d t h v ; p o an ularl r un e and has s w e s e T e a all cu ar icular urfac . h y o d d h o pp d t , g F lavn ssr u unmwwmh

" sa in r sss i n ne i T ccrato smtmtanemis. No. h ft c o ect o ar itsmddle isoval . he distal end isex y p N m 8m U ‘ 8 ' “ M“ 0 m" anded ransersel bu t issmew a c m resse an er se l A p t v y o h t o p d t opo t rior y . natural siz e. A nterior view. com le e ra 1usisnot n wn bu t r xi mal and isal r i ns i e 0 Olm non rocess r con p t d k o , p o d t po t o of t ar , p ; , cavity for proximal end of S hown mfigure 6 6 “ ra dius. O lecranon restored — Fore oot in is n wn th sruc ure th s d romthe ulna of a second in f Noth g k o of e t t of e carpu an f m b “ am" u t little of the metacarpus. Figu re 37 showsall the bonesin the c llec i n r mM n ana a are re ar e as er ainin to th r o o t o f o o t th t g d d p t g e fo e foot of B rachycerat ps.

1 L m L OnV t of the mid-C usf th N west T rri : n r n v t a be . M. ertebra e retaceo o e orth e tory Co t . Canad ian Paleo tolo y ol . 3 . 2 . 60 l. 19 , , g , , p , p , p , fi g. 4 , 1902 . 2 J . S . G ] e M n. 4 . fi . 84 H atcher . B . The Cerato sia: eo . Surv o 9 78 1907 . , , p U y , p , g , 540 25°— 17 3 28 BRACH YCEBA TOPS .

The me acar usisre resen ed one ra men ar and two c m le e me acar als a b 0 t p p t by f g t y o p t t p ( , , , n s 1 fig . but othing i positively known of the positionsthey occupied in the foot . The

es e h fi . alan d 37 are e r e rec an ular emen . wason ph g ( , , f, g, , g ) d p essd t g el ts It account of their thin depressed nature that they were assigned to the menusfor t erwise e a ear in isin uisable r m the , o h th y pp d t g h f o th im th alan es e es. S ilarl e un ual alanx i fi . 37 ph g of p y, g ph ( , g ) isassi ne to the re ein el n a e and m re sar l g d fo foot , b g o g t d o h p y ointe an the s r er m re r a l r un e un ualsasscia e p d th ho t , o b o d y o d d g o t d

wi the ar l articulate in ee . See fi s. 4 6 4 7 . 4 th p t y d h d f t ( g , , pp 3 ,

T P S L VI O GE D “ A l l) m La .

ium— The iliumisan el n a e irre ularl sa e ne Il o g t , g y h p d bo , nsisin a com ara i el thin riz n al ex an e an eri r co t g of p t v y , ho o t , p d d t o s ri part and a nearly vertical bu t narr ower po te or part . (See an The inner and uter bor ers the rsal ace figs. 38 d o d of do f 2 1 ri sm i cur Th r sc e a i e. e ans see fi . 26 . eac e ( g , p ) h d b g o d v t versely expanded anterior plate of the iliumhasa convex dorsal

and a concave ventral surface . The external border isnot con us r m end end asin the ilium Tricerato sand tinuo f o to , of p

' Monoclonius(compare figs. 39 and bu t extendsbackward and downward fromthe anterior portion and fadesout on the — From: m. m imal and distal portions external side above the pubic peduncle. A bove and somewhat of the rad iusof B rachycemtop: montanen ' rwar isermina i n a sec n r un ed r er arisesr m na. O ne fo d of th t t o o d o d bo d f o na l si A r x mal rtion half tura z e. P o i , po ; the outer side of the convex superi or surface of the anterior stal rt n. B , di po io the um d c n inues osteri rl com le in the plate of ili an o t p o y, p t g ou ter border of the middle section and the upper border of the posterior portion. I n ras i t Monocloni' usA athaumasand n co t t wth he ilia of , g , the ilium B rach cere Triceratops(compare figs. 39 and of y isnot nl muc smaller bu t the ranserse ex ansion ataps o y h , t v p of itsan eri r late its rea er inclina i n u war and the t o p , g t t o o t d , differentiation of the thickened deflected border above the ischiac peduncle all distinguish it from the other described ecte r cess forms. In the development of thisheavy defl d p o above the ischi ac articulation and in being longer than the m ar femur it somewhat resemblesthe S tegoeaarusilium. (Co p e

fi s. 26 and 27 . 2 1 and g , pp Near the middle the internal border isgreatly thickened dorsoventrally and isprodu ced downward to formthe su perior is i unc border of the acetabulumand the pu bic and ch ac ped les. ri r un i r er slen er bu t the oseri r one The ante o ped cle s ath d , p t o isexcee in l ea in a imensi nsass wn in fi ures38 d g y h vy ll d o , ho g w n the iliumisin a ertical and . Th se r a e e 39 e po t rio pl t , h v FrG l — nes visionall identified as osi i n hasitssu eri r r er incline sli l u war r m Un 37. Bo pro y p t o , p o bo d d ght y o t d f o pertaining to the fore foot of B rachyccratopc o s hisu er rder is the er en icular. In Brach cerat p p d t pp bo W W I . No. 8079 . S . N . . Su e y p , U M p

rior view. a b c etacar als d e h rela i e in its steri r end iscu t off o li uel and its , , , M p ; , , f, g, , t v ly th , po o b q y al n si un ual halanx. ph a ge : , g p inferior border isconcave fromend to end ; whereasin Tri cerato sit ismuc ic ene its oseri r end is lun l r un e and itsin eri r r er p th k d , p t o b t y o d d , f o bo d “ h r m n th isslightly convex f o e d to end . On e internal side the usual cupped articulating f r he i d s r nd c u ri surfaces o t d apophysesan ac al a a dal bsappear .

1 For convenience inre erence th t on are ca ed under one numer. T d n m t el n ne individ f ese foo b es talogu b hisoesot i ply hat they b o ged to o ual, for they were found among the scattered surface fragments. BRA CH YCEBA TOPB M ON TA N EN SIS GIL M ORE . 29

The measurementsof the left iliumof paratype No. 7953 are asfollows:

Greatest length of ilium Greatest width of anterior blade

reatest width at center transversel . G , y Greatest depth of posterior blade l m Greatest depth at center of acetabu u .

— FIG URR 38 . Left iliumof B roch rawsmontanmis. No. 7953 . S . N . . One-third natural siz e. E xternal view. a A nterior end m p , U M , ;

ac acetabulum; isischiac eduncle; osterior end ; b ubic eduncle. , , p p , p p , p p

P ubis— The u isin B rach cerato sc nsists an el n a e ransersel a ene la e p b y p o of o g t d , t v y fl tt d p t ne a re u ic r i n and a s r slen er cur e smew a rudimen ar oseri r of bo , p p b po t o , ho t, d , v d , o h t t y p t o postpubis. The anterior portion isexpanded dorsoventrally into a broadly rounded end bu t isli ttle thickened transversely . The rugose articulating surface for the peduncle of the ilium isrela i el not so ea asin Tricerato sbut the r a seri rl irec e rocess rmin t v y h vy p , b o d po t o y d t d p fo g the internal wall of the acetabulumisaswell developed asin that genusand contribu testo ' the sam e extent to the formation of the inner boundary of the acetabulum. In none of the

— ili m f B rach N N - s A V ral vi w . Le t u sal FIGURE 39 o cerato s o. 7953 . S . . M. One third natural iz e. ent e o li ue dor f y p , U , ; B , b q

view. a A nterior end ac ta ul m e overhan in crest sterior end u ic ed uncle. , ; ace b u ; o ; b b , , g g ; p , p p , p p

u es e re me isthe s u isen ire all secimenslac in r i ns eir isal en s p b b fo po tp b t , p k g po t o of th d t d ; ns s ri r h r their exte ion po te o ly appearsto be abou t t e same asin Triceratops. The e isno distinct u ic ramen but an e n ate cle be en th s u isan th ene ri r nd p b fo , lo g d ft twe e po tp b d e flatt d poste o e h r is r Th of t e p epub p obably functioned assuch . e greatest length of the left pubisof No.

7953 is192 millimeters. The chief characteristicsof thisbone are well shown in figure 4 1 . I c i' u — In t e e i n ro M n ana er a sh m. h coll ct o f m o t th e are portionsof no lessthan nine ischi of Brach cerato sbut nl one t em1sc m le e e 42 isa l n slen er cur e Se fi . . y p , o y of h o p t . ( g It o g, d v d ne wi an ex an e r xim ex remi carr in a ea articulati nfor the isc iac e uncle bo th p d d p o al t ty , y g h vy o h p d 30 BR AC H YC ERA TOPS . of the ilium and sending forward and u pward a processwhich articulatesat itsextremity i a e isc ia cur e war the me ian ne an with the pubis. The art cul t d h v to d d li d were probably united eir isal ex re ies a by cartilage for a short space near th d t t mit . The sh ft issu bcircular throughout n bu ec messmew a rian ar w n the median part of itsle gth t b o o h t t gul to ard itsreduced distal e d .

The ri isc ium s wn in fi ure 42 . 8073 U. S . . hasa rea es len t 340 ght h , ho g (No , N g t t g h of millimeters.

— Ri t ili mof Tric r N Y O - i s Inferior view a A nterior end FIG URE 40 . h u e ato sabeilanu arsh . o. 18 1 ale useum. nee hth natural ize. . g p fi M , M g , ;

e external border; 1 internal border isischiac eduncle; osterior end; b ubic eduncle. ( A fter Hatchet .) , , ; , p p , p p , p p

" n n - Femur . The femur isrepresented in the collection by one complete bo e a d good siz ed n ers e siz e and differ nl in in r e ailsw ic ma be i sof ur . a h a m port o fo oth All re t e sm o y o d t , h h y

entirely attributed to post- mortemcauses. In B rachyceratopsthe femur isslightly more than one- fourth aslong again asthe tibia and in Tricerato sit is al asl n a ain In her w r sin B rach cerato sthe ra i len t p h f o g g . ot o d , y p t o of g h of the tibia to the femur is1 to and in Triceratopsit is1 to Proximally the head is differentiated fromthe shaft and the greater trochanter by a short neck that islesswell defined thanthat foundinthe femur of TriceratOpsand thatmuch more closely resemblesthe same bone in Monoclonius

r m crassusCope . Viewed f o above the head issubglobu a in u line wi a r un e l r o t , th o d d notch or groove on the ex ‘ ' se o borde I e ternal po t ri r r. h — m N N n - mis. s f B racl cerato s ontaa o. . S . . M. O f na si FIGURE 41 . Left u i o 7953 e hal tural z e: p b w p , U r cl] .an e b fi 43 Internal view. a A nterior end I) osterior end c articulatin surface for u ic eduncle re rea r ( ) , ; , p ; , g p b p ; p g t t o t y g ic m“ Pub W ; isexpanded anteroposteri n e an eri r ex ern an e and e n orly . O th t o t al gl sparated fromthe great trocha ter by a deep cleft

isa a ene fin er- li e lesser r c an er a fi whic risesnearl the ei the fl tt d g k t o h t ( , g . h y to h ght of an cessis n in a greater troch ter. Thispro also prese t Triceratopsbut isshorter and bro der and isa u e u all r minent ex ernall and an eri rl w ereasin B rach cerato sit ism re bo t q y p o t y t o y, h y p o

' prominent externally. Though doubtlesspreserved in Monocloniusthisprocessisnot shown n in the figuresof that bo e by Hatcher. An elongated fourth trochanter restswholly on the proximal half of the posterointemal a In border of the sh ft . Triceratopsthe center of thistrochanter isabout midway between he r ximal and isal en s Th c n s the isal end a e ea the in ernal ein t . e le r p o d t d o dy of d t h vy , t b g lar er an the external . The in erc n lar n c is ee and narr w and the an eri r in er g th t o dy ot h d p o , t o t condylar g roove iswide and concavely rounded transversely and extendswell up on the anterior

e h n Th n a wn in e 43 . Th fac of t e bo e . e pri cipal char ctersof the femur are well sho figur e ea n s s n e w : m sureme t of pecime No . 7953 ar asfollo s

Greatest length Greatest breadth : Proximal end

Distal end sh Least breadth of aft. BaaorrvonmrorsM ON TA N EN S IS GILM ORE . 31

— Tibia The tibia isrelatively short and isconstricted medially but haseXpanded ends. ns n an er se r see fi and the rea es isal easu The greatest proximal expa io is t opo t rio ( g. g t t d t m re n T is n sa i is Th ur a isru sel r u e e . e d s w i n ment istransverse . e proximal s f ce go y o gh d h ho d v o two ac war r ec in c n lesa u su e u al insiz e and se ara e b a narr w in er into b k d p oj t g o dy , bo t b q p t d y o t n res condylar notch of moderate depth . The c emial c t is heavy and proj ectswell forward of the median part of the shaft . The i end is i e in o two sur acesan inner d stal d vid d t f , with a beveled distal surface that articulateswith the astragalusand constitutesmore than one- half of the trans erse iameter of isend and an u er t a ex endsdisall v d th , o t h t t t y to the level of the inferior border of the articulated astragalus and closely embracesthat element on the external side. The anterior side of thispart of the tibia isflattened for the articulation of the fibula. The measurementsof tibia No . 79 57 are asfollows:

Greatest diameter: Proximal end

Antero osteriorl stima d p y , e te Transversely Distal end A nteroposteriorly Transversely

F i — Th fi bula e bula isshorter than the tibia. It is slen er and hasex an e ex remi iesand itssa a en d p d d t t , h ft isfl tt ed in the proximal half but subcylindrical below. The bone is we l n i u inall and the en sare an ate n bo d o g t d y , d gul d to o e

' an er a is lanes asse r u eir l n er diame e oth , th t , p p d th o gh th o g t r if produced would cut one another at A t the proximal end the face toward the tibia isslightly concave and that away fromthe tibia isconvex anteropos teriorly. The lower articular face isflattened and wasclosely a lie e an ri n pp d to th te or flatte ed face of the tibia. The distal articul ar end isshallowly cu pped and triangular in u line itswi es r i n bein in ernal wi a o t , d t po t o g t , th knoblike r ec in ace for the calcane asin p oj t g f t um Camptosaurus. A si e iew the fi ula iss wn in fi ure 4 d v of b ho g 5 . The greatest len the fibula of ara e . 7957 is246 millimete gth of p typ No rs, and the wi e d n greatest dth of th istal e d is34 millimeters.

THE m p F OOT .

— The specimens Notwithstanding the great number of ceratopsian remainscollected in the Rocky Mountain region since 1 85 the resen secimensare the firs b b 5, p t p t to e descri ed F m ” that give an adequ ate conception of the cp mplete skeletal fi i . sru ture f the esmth rne Din sa siz e . External view a P f r a c o e o urra The ar . rocesso rticulation t p ho d . y e of , ww‘ w‘w t tM immd W it is “ p’ p h pub ' additional interest because they pertain to one of the earliest known membersof the ceratopsian group of dinosaursand will be of especial value in deter mining the structural changesthat have taken place in the hind feet of the later and more hl secializ e cera ians the ance w en es hig y p d tops of L h th e are found . sm nr c mr 32 c n ors.

Exce t the vesi ial i i V the c m lete hin t Brach cerato iss wn in fi ure 4 p t g d g t , o p d foo of y ps ho g 6 The elementsdrawn in outline have been introduced fromthe evidence of the partly articu la e se a t d foot No. 7956 ( e fig. in which the ph langesof digit I were present but were turned ac eneat the er a a Th b k b h oth met tarsls. e four th phalanx of digit IV isalso present in that o and isarticulate wi the t ir whic a rees er ec l wi the thir fo t d th h d , h g p f t y th d phalanx of foot

No . 7957 .

— N N - f si A ri r view C anterior From 43 . F m f B roch o. U . 8 . . . One hal natural ze. Poste o external view e ur o ceroto e montanmia. 7953 y p , M , ; B , ; ,

vl r- r ic i r n t r ew. a, Finge like trochante ; b, great trochanter; 13, head ; , nne co dyle; ac, outer condyle; , fourth trochante .

al The pesin B rachycemtopsconsistsof four functional digitsand one which isvestigi . e a i ated ee the halan al rmula hasbeen e ermine as2 4 5 0 ? Fromthese smi rt cul f t p gi fo d t d , 3 , , , In fi re 46 the isdrawn wit the oessrea wi e a ar the se ein tha assume b gu foot h t p d d p t, po b g t d y

e a and whic are firml uni e b ma rix S u the n . m arsals . sec t t I , II, III , h y t d y t t dy of o d foot (No ‘ 7956) and of the opposing surfacesof the metatarsalslendsconvincing evidence that the sur facesof their shaftswere more closely applied throughout most of their length . They inter n an e at eir r ximal en sand us rma c m ac sr n t e . lock with o oth r th p o d th fo o p t , t o g foo

34 BBA C H YC EBA TOPS .

ranserse Th t v . e internal surface Of the proximal end isshallowly concave for better articu lati n wit e o h mtatarsal I . The opposite side isslightly convex and articulateswith the concave ur a e s f c Of metatarsal III . Metatarsal III isthe longest bone Of the foot and in general resemblesthe median element

Of the Tricerato s . The ex ansi n Of the r ximal end isc ie an er oseri rl and p foot p o p o h fly t op t o y, a Of the isal end asin me a arsal is ranserse The th t d t , t t II , t v . distal articular endsOf both a metat rsalsII and III Of foot NO . 79 57 are peculiarly flattened and are not convex antero seri rl asin ms inosaurian me a arsals The en a e s t . s r al po t o y , o d t t d o cu t off somewhat obliquely the l n er iame er the sa s eir aces ein irec e sli l to o g d t of h ft , th f b g d t d ght y inward . Metatarsal IV isshorter than metatarsal II and may be distinguished fromthe other meta r e sa e a tarsalsby the anteroposterio ly compr ssed h ft . Th tr nsverse diameter of the proximal end also exceedsthe ante ro osterior ia p d meter. The inner side near the prozdmal end hasa slightly concave triangular area which artic ulateswell with the convex sur ace Of me a a f t t rsal III . The proximal end isslightly cupped asinmetatarsal IV Of Camptosaurusand Thes celosau rus for t e b , h etter articulation Of the distal arsal elemen . The sa t t h ft , although somewhat con stricted isrela i e , t v ly wi der than in the other metatar sals . The distal face isnearly su are in u line u q o t , tho gh all four sidesare decidedly concave on their median

surfaces. The articular end n x an e isco ve t roposteriorly . Metatarsal V is known only fromtwo fragmentary

— - in f B r cerato smontancnsis. NO. 7957 U . S . N . . One hall natural F ro m46 . Le t h d foot o ach m f y p , M endsW hICh are regarded as siz e . A nterior view. t Tamal bonesof the d istal row; I II III and IV d i itsl to 4 resectively . , , , , , g , p f s imn N Bonesin outline have been introd uced upon the evidence furnished by the foot o pec e O. representing proximal ar

m infi 4 ' ’ g“ 7 a i n ticul r port o s. One of a in a ene n these wasassociated but not articul ated with foo t NO . 79 57 . It is th fl tt d bo e with a rounded articular end that in all probability wasattached to the posterior side Of metatarsal '

n kn wn. IV . The distal portio isun o — an e are s ew a n er an the in erme ia e nes s m l . P halangcs. The proximal phal g o h t o g th t d t o Th anx Of di i iseseciall el n ate e ualin in hismeasuremen the e proximal phal g t I p y o g d , q g t t ’ is e ele O fl war h inn r i e O f he o All I er sur ace e e s t . metatarsal Of digit I . tsu pp f b v d to d t d f ot he alan esare a en l c li e elemen s wit c nca e r ximal and c n ex istal t ph g fl tt ed , b o k k t , h o v p o o v d

ex remi ies bu t lac in the ulle - sa e finis Of the Cam tosaums alan eswi eir t t , k g p y h p d h p ph g th th an h a w a h a a en vertical interlocking keels. M y Of t e phal ngessho shallowl teral pitsfor t e tt chm t a en s The sec n hir and urt alan esOf i i are c nsi era l more f li m . O g t o d , t d , fo h ph g d g t IV o d b y an e t Th a a n and a e roadl shortened than are the phal g sOf he other toes. e ungu lsre flatt e ed h v b y n an er or r erswi i e sur aces Asin Tricerato san S t osaumsin li e ese rou ded t i bo d th p tt d f . p d eg , f th a n were probably incased in flat hoofs. Their articular endsare shallowly concave and h ve elo BBA CH YCERA TOP S M ON TA N EN S IS G IL M ORE . 35

a n a l h a gated oval outlines. In ge eral w y they resemb e t e ungu lsof Trachodon more than those l Tricerato sasfi ure H atcher. of p , g d by — n e n Measurements Measureme tsOf the l ft hi d foot Of the paratype NO . 7957 follow

' Me rementsin millimeterso the le t hind oot o B racll cerato smontanerislsNo asu , , f f f f y p ( .

Greate st length Of metatarsals. Proximal end Of metatarsals: Greatest anteroposte rior diameter Greatest transverse diameter . m l Distal end Of etatarsa s, greatest transverse P ate st l n th : halanges, gre e g

0 N Measurementsfromanother indi xid ual of about the same proportions( o.

RE S TO R A TI O N O F B RA CH YC E R A TO P S .

A complete skeletal restoration Of B rackyceratopsmonta nensis a u one- fifth na ural siz e iss wn in Pla e . , bo t t , ho t IV The total length Of the animal from the end Of the nose to the ti Of the ail isa u 6 ee 9 inc es and its ei h p t bo t f t h , h g t

at the hipsabou t 2 feet 4 inches. Thisrestoration isbased on the remainsOf several indi vidualsand isthe first attempt thusto depict one Of the

earlier ceratopsians. The bonesdrawn in ou tline were not . represented in the collectionsand have been supplied in a m ifi e rm r m er secimens re era l r m se od d fo f o oth p , p f b yf o tho i r rm found in the Judith R ve fo ation. The presacral region hasbeen given the same number Of vertebrae asare found in the articulated seriesbelonging to the type specimen O f o h Tricerat psbrevicornusHatc er. The sacrum el is emra and ail were un in so , p v , f o , t fo d close association that they unqu estionably pertain to one

in i idual NO . 7953 U . S . . In ac the cau al d v ( , N f t , d erte rae were nearl all articul a e and isc m le e series v b y t d , th o p t isOf especial interest asgiving usthe first adequ ate concep f h si s shis tion O t e ceratop an tail . It how t appendage to be considerably longer than hasbeen represented in previous f r si Whe r restorationsO Lance ce atop ans. the thislength cu ing ispeculiar to the primitive formsfromthe Judith River

and B elly River formationsremainsto be determined . The structure Of the fore foot asshown isperhapssome w a c n ec ural al u it is ase on an ar icula e r h t o j t , tho gh b d t t d fo e — L m ' “ GU“ 47' °“ mnd f°°t ‘m Of L e tocerato sa cera sian r mthe E m nt n rma foot p p , top f o d o o fo tanemis. O ne- hali natural

l n Of Cana a a drawm Of wh1ch was ener usl su h d siz e. Shownasiound in lace . Tarsal ones t o d , g g o y pp e p b Of th d istal r w a I II III and IV e o ; , ungual; , , , , b Mr B arnumBr wn Of the Amerl can MuseumOf a ur . o , N t al di its1 to s y g “ a “my. Hlstory . The fewbonesOf the manuspresent in the coll ection havebeen inserted ill accordance with

the evidence Of thisarticulated foot .

her J . B . T Cerat sia: . S . Geo] . S urve M 4 fi Hatc he o on. 9 . 73 d 1907. , , p U y , g ( , 36 BBA CH YCERA TOPS .

The anima isre resen e san in wi the nose r wn wnwar a osi i n a iswell l p t d t d g, th th o do d , p t o th t a a e for the moseffec i e use the sr n nasal rn and a als rin sthe ea wi in d pt d t t v of t o g ho , th t o b g h d th f easy feeding distance O the ground .

The re limsare sr n l exe rinci all on the evi ence Of the well- e el e Ole fo b t o g y fl d , p p y d d v op d r m h s i r i e e i en l ranon on the ulna. The ail sra i l r t e acrum tsisal n in li c t d op p d y f o , d t po t o , f , v d t y si i n dragging upon the ground . The scapula hasbeen placed in a somewhat horiz ontal po t o we wn on the si e Of the ri sin acc r ance wi the e i ence the osi i n Of is ne ll do d b , o d th v d of p t o th bo h Th h r in several articulated skeletonsOf t e trachodont dinosaurs. e great elevation of t e t ans erse r cessesOf the rsal er e rae reachin nearl to the Of the sin us r cessesis v p o do v t b , g y top p o p o , well s wn asisals the rela i e s r nessin ei c m are wi ose Of the an eri r ar ho , o t v ho t h ght , o p d th th t o p t , the sin us r cessesOf t oseri r rsal a d sacral er e rae w ic in Tricerato sare the of p o p o he p t o do n v t b , h h p highest Of the column. The specimen throwslittle light on the proper articulation Of the ischia wi the er elementsOf the sacrum and the res ra i n Of ese neshasbeen ma e in th oth , to t o th bo d accordance with the mounted skeleton Of Triceratopsin the United StatesNational Museum.

A li e res ra i n Of B rach cerato sa u one- six na ural siz e ase on the ar icula e f to t o y p , bo t th t , b d t t d P skeleton (Pl. IV) isshown in late I . The pose ismu ch the same asthat Of the skeleton. It isthe first restoration Of a ceratopsian dinosaur in whi ch an attenlpt h asbeen made to in ica e the n nimbrica in scaleli e ex ure the skin Thisea ure the resore animal d t o t g, k t t of . f t of t d 1 is ase on a recen l isc ere secimen P rotorosauruswi whic well- reser e im res b d t y d ov d p of , th h p v d p f sionsO the skinswere found . a earsair to assume a all the rne inosaurswere c ere a scale in ument It pp f th t ho d d ov d by d teg , h I al though t e pattern of the scal esprobably varied in the different genera. n the present res toration the skin pattern ismodified after the figuresand description given by Lambe . The im ressi n Of the in e umen s wsthe la es a e been enerall five and six si e wit a p o t g t ho p t to h v g y d d , h sunken peripheral margin. In siz e they appear to increase frombelowu pward . Other impres sionslow down on the body indicate that these partswere covered with small tuberclesand that the large plateswere absent . The pattern Of the skin ashere depicted isexaggerated in s Of the a asit w r rac i a em h the iz e l tes as a dl c le re uce th same sc e t e m el. p , h y p t b to d th to e al as od F ll wi n ull in hisres ra i nsOf cera sian ea s a e re resen e the a e Of the o o g L to t o top h d , I h v p t d g p mou th asbeing short .

R ELA TIO N S O F B RA CH YCER A TO PS .

A t thistime it isdifficult to arrive at a satisfactory conclusion regarding the true aflinities Of B rach cerato sfirs ecause Of the ra men ar na ure Of sme Of the secimenson whi c y p ; t, b f g t y t o p h the m re rimi i e cera sian enera are ase and sec n ecause Of the recen isc eries o p t v top g b d ; , o d , b t d ov Of newma eri alsmuc Of w ic isas et un escri e and w ic r mises ma eriall c an e t , h h h y d b d h h p o to t y h g previously accepted viewsOf relationships. 3 In the reliminar acc un B rach cerato s sa e a it w ul a ear mosnearl p y” o t of y p I t t d th t o d pp t y e M o d a er an er f m t s n alli on clonius an in al O re t an wo ears ill l isO ini . d to , ft t v o h y t ho d th p o 3 Br wn hasrecen l re efine the enusMonocloni' us and is efini i n ase en irel on o t y d d g , th d t o , b d t y ac swi two exce i nsw ul u w th skull c ar er a l e all ell e enusBrack cc to s. h t , th pt o o d pp y q y to g y ra p It isasfollows:

Skull small to mediumsiz ed with three hornsnasal horn l r e curved or sr i ht risin frommiddl of sals , ; a g , t a g , g e na immediately above the posterior border Of the nares; supraorbital hornssmall or incipient and flatte ned on the outer surface . Nasalslarge; naresnearly separated by osseousseptumformed by premaxillariesand nasals. Premaxil m ce with vertical late formin se tum nonfenestrated . Crest co o d of short b mosalsand x lari deep p g p , p w , road sq ua e tension Of elongate cood fied postfrontals(parietals) [dermosupraoccipitals] perforated by large fenestrae ; each fenestra r f st ron l derm i M holl within the bounda o the o f ta osu raocc itals. ar in of est nula h min n w y y p [ p p ] g cr cre ted , eac pro e ce bearing a separate ossification. A pair Of long curved hOOklike processeson posterior border of postfrontals[dermo supraoccipitals].

l n th f lim f carni or mur romthe ell River rmation f A l erta and n w f Cerato ia m Lame L . M. O e ore o a v ousdino o o a e enuso s ro the b , , b f B y f b , g p f

kson the inte ument f some cretaceousher iv din urs: Ottawa Nat t l 27 1 l. 14 Jan r 1 14 h remar o orous osa uralis v . . 32 u 9 sane oriz on with o a . , g b . , p , p , y, 3 w w A n din r r mthe Cre f t ith n te n H o urus: Smith . il Gilmre C W . e cerato sian osau o er taceouso on ana o rosa isc o . o c sonian Co . , , p f Upp M , yp M , vol. 63, p . 9, Mar. 14, 1914 . 3 A ml skull i H nius mth ell R iver Cret f A l erta: A M N t t. . 54 m. us a . His ull. vol 33 . 94558 rown arnum co ete o onoclo ro e aceouso . B , B , p , f B y b B , , pp ,

Oct. 8, 1914. BBA CH YCEBA TOPS M ON TA NE N S IS GILM ORE . 37

B rach cera s we er esnot a e se ara e ossificationson the rominencesar y top , ho v , do h v p t p ound “ ” the bor ersOf the cresor rill nor are ere an klike r cesses on the me ian oseri d t f , th y hoo p o d p t or r f d h e a bo der O the ermosupraoccipital. The fenestrae in t e frill are decid dly sm ller than in an rec niz ed seciesOf Morwc iasand it hasnot et been emnsra e a M y og p lon , y d o t t d th t onoclonius h stsn n in B h Th a w a i asal rn ivi e l n i u i all as rac cerato s. e la er e ure ul re re ho d d d o g t d y , y p tt f t o d p ' sen a msim r an sru c ural diflerence r i e suc a ifference can be s wn to exis t o t po t t t t , p ov d d h d ho t, but I amOf the Opinion that when juvenile specimensOf Monocloniasare found they will also w sho a similar development of the nasal horn core. l Lambs has r se a i isi n Of the Cera sia in ree su amiliesthe Centrosa p opo d d v o top to th bf , u . rinae the Eocerato sinae and the Chasmosaurinae name r mthe mos rimi i e mem er , p , , d f o t p t v b of e h is n l wi Ce ar e B wn ach grou p . Brac yceratops i c uded th ntrosaurus(reg d d by ro asbeing a ' n he s i r a a synonymOf Monoclonias) and S tyracosaurusi t u bfamly Cent osurin e. Thissubfamily

“ ‘ isc arac eriz e enera a in re resen a i eswi small r w rnsa lar e nasal rn h t d by g h v g p t t v th b o ho” , g ho , and parietal [dermosupraoccipital] expanded behind short squ amosals. “ A n ar icle B arnumBr wn escri ed the new cera sian inosaur Le tocerato r t by o d b top d p psg acilis, whic he c nsi ersa rimi i e a erran e rela e Brach cerato s. Fur er he sa s h o d p t v , b t typ t d to y p th y “ The complete skeleton will probably show characterssufficiently diverse to warrant founding a new amil to inclu e L e tocerato sand Brach cerato s and r m the ma ria f y d p p y p , f o te l now a a e th two enera a ear be is ise r ma e enera b ar s vail bl e g” pp to d tingu h d f o lli d g y ch acter of he at least subfamily rank . In so far asLeptoceratopsisconcerned t proposed classification is ’ ui e acce a le bu t care ul su Of Brown s a er ails iscl se c arac erss win a q t pt b , f t dy p p f to d o h t ho g th t

Leptoceratopsand Brachyceratopsare so closely related . Certainly a comparison Of the skele a a es c e es B s e n e ra t l r s not re eal suc losaffini i . it i ru el to th Ce o sia and b p t do v h t oth, t , b o g t p oth are iminu i e mem ersOf a r er but ere for the mos ar eir cl se resemb an e d t v b th t o d , th , t p t , th o l c ends. This13 clearly shown by the comparison Of their more important charactersIn the parallel columnsbelow:

Leptoceratops. Brachyceratops.

Small . h S ort and deep . Short and deep . None Well developed

Hi h thin ri t se lttal rid . sa ittal e . Low ob u sa e g , g dg , g g Smooth with ut m mr in ti n Und tin wrth m ian mr i i n , o edian e a g a o ula g, ed e a g nat o . Extendin to ex me sterior border f Short extendin a little more t f g tre po o , g han hal w x m r a to e tre e borde Of crest.

Not etermined . Massive short and dee Relativel slen er of medium l n , , p y d , e gth,

narrow.

Lessthan 15 rowsOf teeth More than 15 rowsOf teeth .

Lar e exte ndi mh sis. t r nt. g , ng to sy p y No p ese n wi Long a d narrow Moderate length and dth . i II mi i D l (8 1 and III ter t n in hOO fs N t known. g , , na g . o

Ossified ulnarsand mdialslar e Do. , g Straight; fourth trochanter comparatively Straight; fourth trochanter moderately 18 developed . Lon and dee “with hi h slender sin s Lon with short heav sinesand rela g p, g . p e g, , y p

v v . and long chevrons. ti ely short che rons

O er ifferencesm be i en for nl the eneric and secific c arac ersasenumer th d ight g v , o y g p h t B wn a n a T se we e a a s w en u un a en a e b r re co rased e. e r e r m tal t d y o t t bov h , ho v , pp to ho o gh f d differencesin the skeletal structure to preclu de the conclusion that they are closely related . That the genusBrachyceratopsrepresentsone Of the more generaliz ed formsOf the Cera topsidae lsapparent ; that it can not be included In either the (Jeratops- Torosaurusor the Eocera

l L B msis . with k ther r f h : C . S M Lame . On o ra o nad mar s ene orned dinosaurs anada Gaol urve b , . , E ce t psca gen nov., re on o g a o Cretaceous y us.

ull. 12. . 20 Ma 7 1915. B p , y , 3 w r m . cit . 1 o n arnu o . 55 . B , B , p , p 3 L to aato sa new en f Cerat r t E m f A l erta: A mM N t. H t. ull. v l. . 567- 5m1914. e c uso o sia om he d onton Cretaceouso . us. a is o 33 p p , g p f b B , , pp , 38 BRA C H YC EBA TOPS .

—Tricera o s lumisals evi en for it is ar l c ncei a le a an animal like Brach cera tops t p phy o d t , h d y o v b th t y s a in a nasal rn sli l n i u inall su ure and an ou r w r mthe nasal nes top , h v g ho p t o g t d y by t tg o th f o bo , could be the progenitor Of later ceratopsianshaving thishorn developed froma center Of ossi n fication distinct from the nasal bo es. Br h e a aren l re resentsa lum c mmencin ri r u i i er time ac yc ratops pp t y p phy o g p o to J d th R v , which either died out before the Lance or the representativesOf which have not yet been dis covered . Family TR A C H O D O NTID A E .

The great number Of their remainsappearsto indicate that the trachodontswere the f T o most abundant dinosaursOf Two Medicine time. Four genera O rachodontidae are n w en ra r c niz e r m the u i i er and B ell i er rma i ns and ese isla g e lly e og d f o J d th R v y R v fo t o , th d p y h nearly asmuch variety Of form and stru cture ast e contemporary Ceratopsidae. In the collection fromthe Two Medicine formation four distinct genera are recogniz ed : (1 ) Hypa sau ruswhic has een re ar e asthe lar es Of all rac on s 2 S te hanosau rus 3 cro , h b g d d g t t hod t ; ( ) p ; ( ) a specimen which istoo incomplete to describe b u t whi ch apparently belongsto an undescribed enus a ma be se ara e rom the crese rac nts H ocrosaurus S au rolo hu s g th t y p t d f t d t hodo ( yp , p , nd harwsau rus its ssession O f a l n srai isc iu mwi u erminal ex ansi n a S tep ) by po o g, t ght h tho t t p o Of itsdistal end and with ilia that distingu ish it generically fromthe Lance trachodonts; and e umerusand sca ula r mthe Two Me icine l cali c m ara le in i s (4 ) a very larg h p f o d o ty , o p b t great w rac n ore and lim r mthe E m nton rma i n O f Al rta now in siz e ith a t hodo t f foot b f o d o fo t o be ,

A m can MuseumO f a ural His r New Y r Ci . the eri N t to y , o k ty

Hypacrosaurusaltispinus? Brown.

Hypecrosaurusaltispinas? Brown isrepresented in the collectionsby a partly disarticu 1 48 U . S . h O f w ic a an x n NO . 79 . t e nes re in e cellen sa e Of lated skeleto ( , N bo h h t t t preser w S ebin n 1 9 1 2 and w vation. The specimen asfound by Mr . t ger i ascollected by me the fOl

m he su si e Of Mil i r in the NW . ec . 27 T r r t e s . 3 w summe 7 N . W l in . 8 . on o g f o o th d k R v , , , R ,

h B f n ian eser a i n Te n C un M n . See P . A . t e lack eet I d R v t o , to o ty , o t ( l II , , p It consistsof h l ramusand u al two cervical r cessesnine sacral cen ra wi sacral ri sfiv d t e eft j g , p o , t th b , e cau als, an an eri r c e r n hree seri r ri sei sines er ainin the rsal and s n t o h v o , t po t o b , ght p p t g to do acral regio , ilium u esle emur i iae and fibulae O f me a ars i n left , both p b , ft f , both t b , both t t i III , d stal portio Of me a arsal five alan es ulnae me acar al and se eral r mn t t IV , ph g , both , t p IV, v f ag e ts. The specimenisOf especial interest asgreatly extending the known geologic and geographic H A f range Of the genus ypacrosaurus. fter a care ul comparison with the description and f h amu n e isin is r m h II fi uresO t e e a l u it t e nl n wn secies . altisinus g typ , I b to d t g h f o o y k o p , p , ’ m h E m n n Cre ace usOf Cana a escri e Br wn. Th s cimn i fro t e d o to t o d , d b d by o e pe e ssmaller and perhapsyounger (asindicated by the open su turesO f the skull and sacrum) than any Of the ical secimens bu t all Of its nes so far as e can be c m are are rem typ p , bo , th y o p d , arkably h d n f H similar in sape an proportio sto those O . altispinus.

The le en ar nearl er ec (see fi . b ut wi u ee and the c m le e u al ft d t y , y p f t g tho t t th , o p t j g ” O f issecimen are al ha is n wn Of the Of H “ (see fig . 49 ) th p l t t k o head ypacrosaurus. I ts footed isc iu m h we er su essthe ro a ili Of itsha in a crese su ll O f the S auro h , o v , gg t p b b ty v g t d k lophusor

S tephanosau rustype. 4 i nd in i The j ugal (see fig . 9 ) isrelat vely short a tscontoursand proportionsisremarkably f ma h similar to the j ugal O S tephanosau rus rginatusLambe. It asa greatest length O f 238 milli f 1 8 metersand a depth at center O 0 millimeters. A scompared with the Lance trachodontsthe dentary Of the present specimen isremarkably I s s44 fi . rea n i 5 mi slender. (S ee g tsg te t le gth llimeters;itsdepth at the middle O f the maga z ine is86 millimeters; the distance in front Of the mag az ine to the anterior end Of the sym

l Gilmore C . W . A newcerato siandinosaur romthe U er Cretaceousof ontana with note n H c mi ni , f o a rosaurus: S thso an isc. Coil. , p pp M , yp M ,

N 1 1914 . vol . 63 , O . 3, p . 0 ,

‘ 3 rown BarnumA newtrachodont dinosaur H ecrosaurus romthe Edmonton ( N retaceousf A l erta: m. Mus at is , , f o b A . . H t. ull . vol B , yp , B , .

- 1 13 . 32, pp . 895 406, 9 ? H YPA C BOSA U BU S A L TISP IN US BRO W N . 39

— mrsf N N n - n ral si Inte vi w. G RE 48. Lelt dentar Oi H ocrosaurusaltisi rown. O. 7948 . 8 . . M. O e fourth atu ze. rnal e FI U y yp p B , U

F —L e t l imu f rown. No. 7948 . S . N ne- half t l siz e. Lateral view. a A nterior IG URE 49 . achr mal oi H ocro cu slur . M. O na ura f y yp sm p B , U ,

end; posterior end .

— - F E R i t ili moi H ocr i l r N S . N . . O ne ei h th natural siz e. L ateral view. lOUR 50. h u oeaumsout ms rown. . 7948 . g yp sp B o , U M g 4 0 BRA C H YC EBA TOPS .

— FIG E 51 . Leit isi H acmsumsaltb imnf N UR u o a rown. o. 7948 . Ono iourth natural siz e. External view. p b yp p B , U

physial surface is120 millimeters; the length of the n m 2 3 im h e al a az ine is 9 mill e ers. as39 d t g t It ,

ssi l 40 a lar roo es. po b y , lveo g v The distance fromthe front of the dental maga z ine to the end of the symphysial surface isrela tively shorter and hasa more abrupt downward deflection in the Ju dith River formsthan it hasin

those fromthe Lance.

The ilium (see fig. 50 ) hasa strongly arched su eri r b r er wi a reace abular r esscom p o o d , th p t p oc pressed and of almost uniformtransverse thickness;

the pubis(see fig . 5 1 ) iscomparatively short and has i itsanterior port on broadly expanded .

Well - preserved anterior and median caudal vertebrae are shown in

— — v te ra Oi H ecrosaumsatti FIOURE 53 . ed ian caudal verte ra of H ocrosaumsalti From 52. A nterior caudal er b yp M b yp

si r wn N . N . . O n - t t s . nne ro . o. 7948 S . e our h na ural f rown o. 79 48 . 8 . N . M. O no hali natural iz e spimlsB . N , U p B , U M f “ sid . si . V mri t e Viewed fromleft side. z e iewed fro gh

4 2 BBA C H YC ERA TOPS . undescribed genusor pertain to one of the described membersof thisgrou p that have been ase on skullsit isnot ssi e sa t isi e b d po bl to y a th t m . The specimen wasfound about a mile below the abandoned ranch bu ildingsof John Ed war son the su si e the ri er at the base the i ex suresa u the mi le the d , o th d of v , of h gh po ( bo t dd of Two Me icine rm i n 1 T a . See fi . . he nesrecei e are two ilia two isc ia d fo t o ) ( g , p bo v d , h , two rsal and ree cau al er e rae ree c e r nsan ra men ar ar s d . do th d v t b , th h v o , f g t y p t The isc ia see fi slen erer an se in an escri e rac n in . 55 are o a an h ( g ) d th th y d b d t hodo t , h v g extreme length of 880 millimetersand a diameter acrossthe iliac and pu bic headsof 230 milli ers T e os sri i met . h m t t king feature of the ischia isthe presence on the infer or border of the ex n e en a e i ica or me - li e n c ance r c s a d n ll l a n fi . In the a n ere p d d of pt f k ot h (f, g L t hodo t th isusuall sli in en a i n in and S aurolo husthe lace isen irel incl se y ght d t t o po t , p p t y o d

— - s In vi F n . R i ht den ar i ha sau mar " L N N O n hal natural iz e. ternal ew. la t: 54 t of e no me . o. 2 . S . . e u S rus inalize a 805 . g y p g ( b ) , U M f

ne rmin a ramen In H acr saurusthe isc iumsowsa l n sall w in en a i n by bo fo g fo . yp o h h o g, h o d t t o r i L r mo e like that n the ance t achodonts. B w h x x u l and c n inues asa l n elo t e e panded pro imal end the shaft contractsabr pt y o t o g, Th inn r sur ac he isal slender rod that expandsonly slightly toward the distal end . e e f e of t d t

wo- ir sisl n i u inall sria e in ica in th li amen al uni n wi itsma e the t th d o g t d y t t d , d t g e g t o th t of oppo T m u in nd rmasin S au rolo hu sand site side. he iliu (see fig. 56) hasabou t the same o tl e a fo p c ss H au . er icall it isnarr wer an in H acrosau rusand the reace a ular r e ypecros ms V t y o th yp , p t b p o ’ w a ree wi C e s rie descri isflattened and isrelatively longer and narro er. It appe rsto ag th op b f p ' 1 P C Wh e er it s ul be re erre a rm tion of the iliumof teropelyr grallz pes ope. th ho d f d to th t fo

d m h i iliu mar i en el w. remainsto be determine . Measure entsof t e r ght e g v b o

Greatest length

Depth at cente r of acetabulum Length of preacetabular process

Length of postacetabu lar process.

i mie: A merican N aturalist vol. 23 . 904 1889 . D . N teson the Dinosauria o the Lara , Cope, E . , o , , p EUROP LOCEP H A L U S . 4 3

Trachodont gen. and sp. undet.

A . 55 U S N M. n xc sca ul a and umerusN 79 . . . a e ee in l la e rac n re p h ( o , ) of d g y rg t hodo t ptile c Tw M Pl B fi 1 Wh h m were c ll e te on o e icine i er. See . and . . ile t e a erial is o d d R v ( II , , g , p t s n rmin h enusand secies w ic it el n sthe secimen is i in ufficie t to dete e t e g p to h h b o g , p of nterest on account of itsresembling most nearly a fore limb and foot fromthe Edmonton Cretaceous h A m can Musum a ural C na a nowin e eri e Histor . of a d , t of N t y

— Fia a Lelt mof unid ont re tile. No. 8 N . On - i t l si E N tch nn 55. ischiu entified trachod 8058 . . . e e h h natura z e xternal view. o p , U M g . I, i iliumarticulation; ubic articulation. , p, p

Th masurements w er s w a the s imn h s d muc e e , ho ev , ho th t pec e asa maller scapula an a h l l n er umerus an aurolo h o bo i' and iff nc sa r m o g h th S p uss rn , these d ere e t once separate it f o that

genus.

' Com iv m r in millim o arat e ameménts icra Trachodon s Tr tm nd aurolo h osborm. p , , f p ., achodon annec , a S p us

No 795 (No. 5220 , e N e M A m Mus

Nat. Hist”)

Greatest length of humerus st ransverse diame r distal nd Greate t te , e

0 Estimated .

— FI E Ri il m f d l N - i vi w GUR 56 . ht iu o i i . 8 On hth t sz e. Lateral e . uni ent fied trachodont re t e. o 8058 . . N . . e ei na ural g p , U M g

Family ANK YL O S A UBIDAE .

Europlocephalussp.

coossifi d r fi 5 i ifi as r A e t ansverse row of dermal platesor scu tes(see g. 7) is dent ed pe T w taining to thisgenus. he keeling of the scu tesdifferssomewhat froma ro of platesper ainin the e Eu ro loce hal tut am e r mBell i er Cana a asfi ure t g to typ of p p us usL b , f o y R v , d , g d by z L ambe .

1 m The kele f a o - C : A mM N t H t . rown arnu s ton o S ur lo husa crested d uck illed dinosaur romthe Edmonton retaceous . us. a . is. ull B , B , p , b f B , 1 1 vol. 32, p . 392, 9 3. 3 me L . M. On V erte rate of the Mid - i th N w t T rit r : C r C Pal v . t. 2 l. 12 fi . La b , , b Cretaceouso e orth es er o y ont . anadian eontology , ol 3, p , p , gs

3, 4, 1902. 54025° — 1 7— 4 smcnr cnmro 44 rs.

The secimen was un on Milk i er a s r isance r mth l w e p fo d R v , ho t d t f o e p ace h re the type of Brach cemto smontane ' was isc er a a li i riz n sts wo nsis e t s r . c n i y p d ov d , ghtly h ghe ho o It o s of t en ire scu esand a r i n a hir al fi rm o ifi d Th l co ss . un u a t t po t o of t d , l y e e der srface is rched trans h versely and probably representst e first row of platesposterior to the skull. The platesare su rec an ular in u line wi er an l n wi a rais median n a is n r b t g o t , d th o g, th ed portio th t lo ge than wi e and issurm un e a lun nodelike sine asmme ricall c w d , o t d by b t p y t y placed , asontrasted ith the sharply keeled scu tesof EuroplocephalustutusLambe . The uni n the la eson the rsal sur ace is lainl iscerni le but h u ur o h o of p t do f p y d b , t e st es n t e r m en ral si e are en irel li e a e . ascular ar in sare c nsicu uson the u er surf c v t d t y ob t t d V k g o p o pp a es, i on h m i n fi A espec ally t e raised edian port o s. (See g. 57 lthough thisspecimen isidentified as er ainin the enusEuro loce halusit mi wi e ual r rie be re rre A p t g to g p p , ght th q p op ty fe d to nky lo au or it ma re resent an un cribe rm. s rus, y p des d fo

— mo t: 57 D l f s N . 8 - l mal ha . o. 794 . N O hird un . er ateso Eure oce s 3 . l . ne t natura siz e. p pl p lu p , U

ssC HE LO NIA Cla .

Basilemyssp.

The enusB m isre resen e ra men a ar th car d asr n g asile ys p t d by f g t ry p tsof e apace an pl t o , se eral er e ral cen ra one umerusand r mn r lim n all ar e as el n v v t b t , h , f ag e tsof othe b bo es, reg d d b o g in on in i i . 24 U . e u al 80 . S . g to d v d (No , N

D 0 P . H a w k n im in h n d h r. . in u n m s in e s ime an e is y as d e o gh to spe d so e t e tudy g t pec , of the ini n a it bel n sei er to B m no i H a the e w ic isromthe e sin op o th t o g th asile ys bil s y, typ of h h f b d N wMexic cri B wn h O A lam ma i n or a c sel rela e seci e es e r to l es. o d bed by ro ast jo o fo t o , o y t d p B i hasasits isin u in c arac er a i ri e o wall ar un he u er si e . nobil s d t g ish g h t h gh dg , r , o d t pp d of h im ' the hinder lobe of the plastron. In t e spec en thisridge ishigh in front but isreduced T farther behind and israther fiat. hischange may possibly be due to individual variation. T w 2 T 3 o h u M h s cim un . . 8 W . n i ilk i r e en as e. 7 7 t e s s e p fo d in se , N R , o th de of R ve , H somewhat below the horiz on in which the ypocrosau russkeleton (No . 7948) wasobtained . The specimen isof interest asapparently corroborating the dinosaurian evidence for the correla w ’ A ‘ tion of the Belly River formation ith B rown sOjo lamo formation.

1 t N M m. M N t t v 1914 . S Pal de i sa the SanJuan asin . ex: A us. a . His. ull. ol. 33 . 302 303 inclair W . J . and G ran er Walter eocene ost , , g , , p B , B , , pp , , I N D E X .

P age. Acknowled mentsto those aidin l Brach cerato smontanensisG ilmore—C g g y p ontinued.

Basilemyssp

alisphenoid oi .

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o

o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o

viewsoi l oi v ews vertebral columnoi rown arnumdefiniti B , B , onby viewsof onCeratopsia i l exoccip ta oi Cerato sia develo m p , p ent of . occurrence of

viewOf 33 s Crocodile , occurrence oi . 274 8 Cut ank ont ossilsfr v B , M , f om icinity oi viewsnear

D w 0 . a son M . on Belly River formation measurementsof 35 viewof d mal latesi w er p o , Vie of 28- 29

29 ' 3° dentary of, viewof

soi view f pubi , o

Judith River formation lati , corre onof

Knowlton F . B . on flora of Two edicin f , , M e ormation

Lambe L . S . onsubdivision f , , o Ceratopsia ilk River ossilsrom M , f f viewson Mmtana r u col mnar sectionof g o p , u correlationof

Stanton T . W . onfauna of Two edicine format , , M ion Stebin er Eu ene onstrati ra h of Two edicine ti g , g , g p y M forma on.

Stra rer J . . w k of . y , P , or Trachodont

dentary of viewof ,

I , 34 ischiumof viewof 25- 20 , Turtlesoccurrence of 25 , Two edicine ormation emulationof 15 M f , 16 o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o o strati ra h of 21- 24 g p y viewsof views0‘ 20, 21 , 22 28—27 27 8—18 measurementsof 18