Vol. 70.] MOLLUSCAN REMAI~'S FROSt TIIE VICTORIA NYAmZA. 187

APPE~'I)Ix III. On-some.NoN-~'LtRI~'E MOI,LUSCAX RE.~IAI.~'S f,'Om the VICTORI& ~N~YA~XZA ]{EGION, ASSOCIATED with MIOCENE VERTEBRATES.1 ~BV RIclI.tl~D BULLEX NEWTON, F.G.S. ~PLATE XXX.] Introduction. The material on which this eomlnunication is based wa~ obt;tined by Dr. ]~elix Oswald from a series of fluvio-lacustrine deposits occurring at ]qira, Kachuku, and Kikongo, which are situated cast of Karungu Bay, and therefore near the north- eastern corner of the u Nyanza, the furthest-removed locality from the lake-margin being Kikongo, which is distant some 5 or miles. From geological observatiofis made at these places, Dr. Oswald was able to construct a vel%ical section showing that the rock-suc- cession was divisible into thirty-seven beds of variable thicknesses, which, when added together, amounted to a total thickness of about 160 feet. Speaking generally, the mollusea were found through- out the deposits, and often in association with a snmll species of DinotJ~erium, and Chelonian, Croeodilian, and other vertebrate remains. The most valuable of these fossils was the Dinotherium, beeause it unmistakably indicated that the deposits containing it might be referred to the Burdigal!an stage of the Miocene Period. S~-atign*aphically, then, this was an important result; but it had been arrived at previously to the ' Oswald' expedition by Dr. C.W. %ndrews, F.R.S., ~ who reported on similar Dinotheriun, remains tom the same area, which had been collected by the late Mr. D. B. P~gott, and were afterwards presented to the British Museum by ~r. C.W. Hobley, C.M:.G., one of the Commissioners for ]}ritishEast Afriea. From a fragmentary mandible with teeth in sit,~, Dr. Andrews was enabled to recognize a new species of this , figuring and describing it as 1). hobleyi, as well as pointing out its affinities and ranking it as 'closely similar to D. cu~ieri' of Kaup, a characteristic mammal of the Bm'digalian beds of France. It is fortunate, therefore, that the vel~ebmte evidence enables us to determine so accurately the horizon of the deposits, because the molluscan remains would have utterly failed in this direction, from the fae$ that they represent existing species. The collection consists entirely of g'astropod gener~ of fluviatile and terrestrial character belonging to Amjoullaric~, Zanistes, Cleopatra, T,'opidophora, Achatina, Burtoa, Cerastus, and Zimicolaria--the total aosence r Peleeypoda being incidentally mentioned as remarkable, since 1 Communicated by permission of the Trustees of the British !~Iuseum. .o , On a New Species of Dinotherimr~ (D. hob~eyi) from British East Africa' Proc. Zool. Soc. London, 1911, p. 943 & pl. xlviii. 188 ~1~. R. B. ~'EWTON O~" ~'OX-MARI5-E MOLLUSCAN [June ~9 ~4,

the group is so well represented in the waters of the Victoria Nyanza at the present day. The more abundant shells are the freshwater genera Ampullarict, Lanistes, and Cleopatra; whereas the remaining or terrestrial forms are few, and appear to be extremely rare. So far as past distribution is concenaed, only three of the species have been pre- viously recorded from geolo~eal deposits: namely, Ampullaria ovata and Zauistes carinatus, both of which occur in the late post- Pliocene beds of Egypt (Fayfim) ; and also ~'opidoThora nyasana, which has been found in beds of similar age on the Lake Nyasa plateau. Among the freshwater forms, only the ,~mpullaria is known as living in the Victoria Nyanza, while the nearest water for Zanistes carinatus appears to be the Tana River, a consider- able distance east of that lake. Lake Rudolf and the Mombasa- Zanzibar waters are the nearest available regions for obtaining- ~leoflatra buh:moides, while C. exa~'atct is found only in the last- named district. The land-shells are mostly restricted to the Nile and lake countries of Eastern Africa. In the following table the dista'ibution is set out more fully :-

TABLE SHOWII~O THE DISTRIBUTION OF THE SHELLS COLLECTED BY DR. OSWALD.

:, : ]Recent.

, ~i=~ ~ ",~= .,!~: I ~,~ Genera and Species. I'. t~l:., .,"~_1 .,,.-. ~.~

i~:_i~___l~___!~_Z_l = -et~. __ N ~ Freshwater.

,4m2aullaria ovata ...... X X ... X X iI• "'" X ]Lanistes earinat~es ...... )< X ... )< Cleopatra bulimoides ...... X Cleoyaatra exarata ...... X .. ~ ...... Terrostrial. 1 Tropidophora nga#ana .... X ,.. ~ .., Aehatina sp...... I ,,( Burtoa el. nilotiea ...... i :K ...IX Cerastus cf. moellendord~ ' X ...... • • Cerastus sp ...... i X : i Limicolaria sp...... "l 1 i i In no other region of Africa has a similar molluscan fauna of this age been found, the only Burdi~lian beds known being those of Mogham 1 and Wadi Faregh ~ in Egypt. They are, however, differently constituted, having involved marine as ~Tvellas estuarine conditions in their formation, as proved by their fossil contents, which consist of marine , eehinoids, polyzoa, etc., as 1 C. W. Andrews, Geol. lV~ag,dec. 4, vol. vi (1899) pp. 481,482. : E. S~romer, Abhand/. Senckenb. Natttrf. Gesellsch. vol. xxix (1907) p. ~3. VOt. 70.] RESfAI.NS :FROM THE YICTO:RIA I~YANZi 1REGIO~N'. 189 well as land- (Bodoc~e,~is, Brachyodus, etc.), and plants (palms). Ccl~ain sandstone-beds in the Moghara region are inter- calated with marine and terrestrial deposits, and are full of the small _Palu(leslrina (=Z-[]/drobia): hence Dr. M. ]31anckenhorn I has regarded them as equivalent in age to the 'Hydrobien-Schichten ' of Europe, which is part of the Burdigalian stage of the Miocene. It would seem, therefore, according to Dr. Oswald's z preliminary account, that the deposits in question represent the delta of an old river which, during Lower Miocene or Burdigalian times, ran into the Victoria Nyanza at Karungu. The present molluscan evidehee would indicate that the genera Za~tistes and Cleopatrcl formed part of the lake-fauna at that period, although they have since become extinct in those waters, only the AJnlndla~'ia surviving to the present day. Among the terrestrial shells, Burtoa, is the sole genus found in the neighbourhood of the lake, whereas the others occur in locaEties at considerable distances therefrom. Finally, it may be stated that the molluscan renmins consist largely of natural casts in clays, marls, and sandstones of different shades of colour, the .prevailing tint being grey; there are, besides, occasional specimens which are better preserved, and in which the details of shell-structure can be seen. I desire to thank my friend Mr. Edgar A. Smith, I.S.O., of the British Museum, for advice and assistance during the preparation of these notes.

Description of the Specimens. Freshwater Forms. Family A_~u,tT~mxi~rn)~. A~[PVLn.tRLt OVXWi Olivier. (P1. XXX, figs. 14.) Arnp~dlaria ovata Olivier, 'Voy. Emp. Othomau, ]~gypte, Perse' 180~ (An 12) vol. ill, pl. xxxi, fig. 1 & p. 67 : E. yon Martens, ' Beschalte Weichthiere Ost- Afrikas--Deutsch-Ost-Afrika' (K. MSbius) vol. iv (1898) p. 158 ; E. A. Smith, Prec. Malac. Soc. London, vol. vi (1904) p. 100. :Pachglabra ovata Kobelt, Kuster's ~Conchyl.-Cabinet ' pt. 556 (1912) p. 46. Original diagnosis :--Oblongo.ovata, subcarnea, i~tus alba ; umbilieo angusto, recurve ; marffi~te columellari obtecto. R e m a r k s.--The specimens referred to this species consist mostly of matrix-casts of various sizes, with more or less imperfect and fractm'ed margins. In adult forms the spil~l region would appear to be rather more produced than in smaller specimens--although the relative proportions are similar, and entirely agree with what obtains among living shells brought home by Dr. Oswald from the waters of the Victoria Nyanza. A few of the smaller or inter- mediate examples have some shell-structure preserved, in which the longitudinal sta%tions can be traced; but there is no evi- dence of the spiral bands. * Zeitschr. Deutseh. Geol. Gesellsch. vol. liii (1901) p. 102. 'Daily Telegraph' April 5th, 1912, ~nd Geogr. Journ. vol. xli (1913) p. 114. 190 .~R. 1~. B. 5-EWTON OS NON-)I&RINE MOLLUSC&h" [June 1914, OccmTing with these specimens are a number of isolated opercula of large, thick, and robust clml~cter, and, nmreover, of calcareous stl~cture. Only one fmgmentalT example is obselwed to be more or less in situ, covel~ing the broken aperture of one of the smaller forms of this species. Dimensions in millimetres:-- Shellf Height varying from 18 to 45. Diameter (maximum) varying from 15 to 45. O , f Height = 33. percu~um ~[ Width=20. Distribution.'-Although there are no rccoMs of the existence of this species in the waters of Birket el Qm~n, it occurs in the late post-Pliocene deposits of that district of Egypt (exalnples are pre- served in the British Museum and in the Cairo Musetun). Besides the original locality of Lake Mareotis, this mollusc has been found in the region of the White Nile, the Victoria Nyanza, Lakes Tan- ganyika and Nya~, as well as in parts of Portuguese West Africa. Occurrenee.--The specimens were mostly discovered in Beds 1~ & 15, associated with re~mins of Chelonia, Crocodilia, and Lanistes carinatus. More isolated examples are represented from the following beds :- Bed 16. Opercula only--associated with Hymcoid, Crocodilian, and Chelonian remains and Gleopatra. Bed 17. ~ Accompanying Chelonia and Crocodilia. Bed 19. J * Bed 21. With Lanistes carinatus, and vertebrates similar to those found in Bed 17. Bed 2"~. Opercula only--with 3)inotherium and other velffe- bl,-ltes. Bed 31. With Dinotherium and other vertebrates. Bed 32. With I, a uistes carinatus and Cteopatra. Bed 34. An isolated cast in brown marlstone. Localities.--Nira (Beds ]r 15,19, 24, 31, 32, 34) ; Kachuku (Beds 14~, 15, 16, 17, 21, 2'~); Kikongo (Bed 14).

Lx~IST~S CAUL~XT~-S (Olivier). (P1. XXX, figs. 5-7.) Helix te~restris bolteniana coutraria Chemnitz, ~Conchylien-Cabinet' vol. ix (1786) p. 89 & pl. cix, figs. 921-922. AmTullaria carinata Olivier ' Voy. Emp. Othomalu Perse' 1804 (An 12) vol. iii, pl. xxxi, fig. 2 & pp. 67, 68. .[~anistes oli~ieri Montfort, ' Conchyliologie Syst6matique' voL ii (1810) p. 123 (=earinatus Olivier). Lanlstes earinatus E. yon Martens, 'Besehalte Weiehthiere Ost-Afrikas-- Deutsch-Ost-Afi'ika' (K. M5bius) vol. iv (1898) p. 169. Meladomus (Zanlstes) carinatus Kobelt, Kuster's 'Conehyl.-Cabinet' pt. 550 (1911) p. 19. Lanistes earinatus 12. B. Newton, Prec. ~Ialae. See. London, vol. x (1912) p. 75. Remarks.--The principal chal~cters of this species are well epitomized in Olivier's diagnosis of 1804 :--'A.~ieuLr, xaIx cx~I- ~xTx : sinistra, depresso-turbinata ; umbilici maximi qnargine carinato; a pertura suborbieulata.' For the more modern inter- Vol. 70.] RE~iIXS r~o~ THE VICTORIi ~'riXZi ~EeIO~. 191

pretation of the shell, however, it is necessary to consult the figures and description of Dr. W. Kobelt as published in 1911, although exception must be taken to that author's recognition of it under the genus ~]Ieladomus. 1 It is more correct to regard 3leladomz~s as embracing those species of reversed shells allied to Lanistes that have produced spires, and are besides mostly imperforate or simply furnished with a slit-like opening~as opposed to the true Lanistes, which exhibits a spreading and depressed spira,1 region, as well as a deeply-excavated mnbilical cavity. The present species, therefore, to which the fossils ara referred, forming the type of Lanistes of ]). de Montfort, 1810, should not be mistaken for a member of Grav's later genus, Meladomus. The fossils, numerously represented in the collection, consist chiefly of matrix-casts, composed of dull greyish clays or nmrls frequently tinged or mottled externally with (lark reddish brown. They are particularly characteristic of Beds li & 15,'being also found in Beds 21, 22, & 32, although much less sparingly and of smaller size. Occasional shell-structure has been preserved, in which the finely-carinate sculpture of the spire can be traced together with the growth-striations. As in the recent shell, ~he peripheral carina of the fossil form gradually disappears in its later development, the last whorl exhibiting considerable in- flation and roundness. The height of the spiral region may also be mentioned, as showing slight variation both in recent and in fossil examples. It is a significant fact that no opercula of this mollusc have been found, their absence being probably due to the extremely delicate character of that organ, as also on account of its comeous textm'e, which would favour its entire dissolution during the processes of fossilization. Distribution.-This species is known from the younger post- Plioeene deposits of the Fayfim depression in Egypt (specimens in the British Museum and the Cairo Museum), and is found living in the Nile (near Alexandria, etc.), Birket el Qurun, Lake Dembea (Abyssinia), and the Tana River in British East Africa. It apparently does not belong to the present-day fauna of the Vietol% Nyanza, no specimens having been found among a large series of shells brought back from that lake by Dr. Oswald ; nor are there any examples in the British Museum collection. Dr. E. yon Martens' has referred doubtfully to its occml'ence in the u Nyanza; while Mr. E. A. Smith ~ has regarded as unreliable Dr. tI. Dohl~'s statement ~ that the species exists in those waters. According, 1 Meladomus was originally proposed by W. Swainson (' A Treatise on ~r eology' 1840, p. 340), but without recognizable type or description. Its proper adoption was due to J. E. Gray (Prom Zool. Soc. London, 1847, p. 148), who selected as its type G. B. Sowerby's Pa~udina olivacea ; therefore to Gray must be accredited the authorship of this genus. ' ' Beschalte Weiehthiere OsbAfrikas--Deutsch-Ost-Afrika ' vol. iv (1898) pp. 169, 290.- 3 Ann. Mug. Nat. Hist. ser. 6, vol. x (1892) p. 121. Proc. Zool. Soc. London, 1864, p. 117. 192 ~R. R. ~..~'EWI'OX O~" XO.~-~X~I~'~: MOL~.CSCX~" [June 19 ~4, also, to E. von Martens, the species does not occur in either Lakes Tanganyika, Albert Edward, or Nyasa, nor has it been recorded from I~lke Rudolf; the southelaamost locality for the shell appears to be the Tana River in British East Africa., 1 distant probably some 600 miles Jeast of the deposits whence Dr. Oswald collected his fossils. Occurrence.--The specimens found in Beds 14 & 15, which are the most numerous, were associated with Chelonian and Crocodilian remains; the specimens from Bed 32 occurred with AmTullaria and Cleopatrce. Localigies.--South Nim (Beds 14 & 15); Kachuku (Beds 1~ & 21) ; Nim (Beds 14 & 32).

Family Vlvn,~t~IJJ,~. CLEOPATR.k :BULIMOIDES (Olivier). (PI. XXX, figs. 10 & 11.) C#elostoma bulimoldes Olivier, ' Voy. Emp. Othoman, l~gypte,Perse' 1804 (An 12) vol. iii, p. 68 & pl. xxxi, fig. 6. t~aludina (Cleopatra) bulimoides Troscbe], 'Das Gebiss der Schnecken' 1857, vol. i, pt. 2, p. 100 (Cleopatra, founded on the structure of the radula, Olivier's bulimohles being the type) ; E. yon Martens, ' Conchylien aus Zanzibar, &c.' Nachtr. Deutseh. Malak. Gesellseh. 1869, p. 154. Jiekeli, Nova A'eta Aead. Cms. Leop.-Car. vol. xxxvii (1874) p. 2/4). 0 r i g in a I d i a g n o s i s :--Parvulum, fusiformi.oblonyum, eorneum ; zona fusea, ~mbilieo augusto, apertura ovali. R e m a r k s.-- Upwards of a hundred specimens in various states of preservation represent this small species. They are of conical oblong contour, possessing about six convex whorls, a slightly oblique, small, and oval aperture, as well as a rather insignificant rimate perforation. The sm~ace is marked by a series of irregular longi- tudinal striations, sometimes sinuated near the suture, the earliest or apical whorls being more or less ang'ulate immediately below the suture and, moreover, furnished with strong spiral eost~e. It often happens in recent examples that deeortication of the apex has taken place, and thus destroyed this early spiral sculpture ; it can 5e obscure b" seen, however, in a British Museum specimen (among others in the :~une box) collected by Capt. S. S. Flower, a~ Giza, Egypt, but in the fossil examples this ornamentation is far better preserved. There appear to be no figures illustrating such sculpture, although it constitutes an important feature in the histon, of the species. References have been made to the uniearinated condition of the uppermost whorls both by Jiekeli and by E. yon Maidens ; but, so far as the presence of sl)iml eost~e is concerned, such a character would appear to have hitherto escaped the notice of eoneholo#sts. D i m e n s i o n s in lnillimetres :- Complete sl)ec,ime~ Imperfect specime~ of larger size (medium size). (three last whorls only). Height ...... 13 ...... 15 I)i~me~er ... 7 ...... 8

I E. yon Martens, Monatsber. K. Preuss. Akud. Wissenseh. 1878, p. 296. ~'ol. 70.] RESfAISS FROM THE VICTORI& .A-YASZA REGION. 19:3

D i s t x"i b u t i o n.--This is a characteristic mollusc of localities ill North-Eastern Africa and was ori~nally described from Lake :Mareotis. De. aiekeli refers to a number of places where the shell has been found, mostly in the Nile waters. According to E. yon Martens, the speeies is not known to exist in the Yictoria Nyanza or in the other lakes of that part of Eastern Equatorial Africa ; it has, however, been recorded from Lake Rudolf bv NmwilM & Anthony.1 Oeeurrenee.--The specimens were found in a brownish marl- s~ne, associated with A~q~dla~'ia and Zanistes, in Bed 32; and in Bed 31 associated with Am])ultavia and Zimieotavia. Loeality.--Nira. CI, EOPaTR.~ EXXRXTX (E. yon Martens). (PI. XXX, figs. S k 9.) Paludomus exarata ~" cingulata E. yon Martens, Monatsber. K. Preuss. Akad. Wissenseh. 1878, p. 297 & pl. ii, figs. 14-16 (=cingulata'of the plate). Cleopatra exarata Bourguignat. 'Moll. Afrique ]~quatm'.' 1889, p. 164,; E. vol~ Martens, 'Besehalte Weichthiere Ost-Afrikas--Deutseh.Ost.Afrika' (K. MSbius) col. iv {1898) p. 189. Cleopatra (Zanguebaria) e.varata tV. Kobelt, Abhandl. Senckenberg. Natm'f. Gesellscl,. col. xxxii (1909) p. 80. Original diagnosis :--Testa eonieo-ob longa, perf orata, sol ida, ein.q,d i8 spiral ibu, elevatis eonfertis, circa 9 in m~fr. penultimo conspieuis, nltra 20 i~ ultimo, non- nullis bifidis, senlpta, niqrieans deeollata ; anf,', superstites 4, vix eonvea'iuseuli, sutura medioeri disereti ; aperhwa subperpendieularis, oblon.qo.auriformis, superne aeutanffula, margine ea'terno anffulatim are~tato, basali aurieulatim produeto et eff'uso, eolumellarl subdilatato, e.rpanso, fulvieante. Remarks.--Thcre are several fmgmenta D- examples of this speeies, in which the eharaeteristic and spirally-banded eost~ are well preserved. The most complete speeimcn has escaped anything like erosion of the spire, so frequently the ease among recent forms. This has a length of 15 and a diameter of S millimetres; it is funaished with seven or eight whorls, the protoeoneh being rounded smooth, and depressed, the two succeeding whorls being more or less smooth, el'eeL and earinated in the eentre; the later whmqs are of more plano-eonvex structure, with the exception of the last, which is elong-ately inflated. The peristome is ineomplete, on account of the outer lip being fi'aetured ; the base is, however, well preserved, and shows the produced character of the lip of the eolumella, together with indications of a narrow perforation. It should be mentioned also that the ein~mdate eostm are crossed by innumer- able, fine, microscopical striations, which give rise to a delieaMv- deeussated surface. Distribution.--The species appears to be restrieted ~ the Zanzibar and Mombasa regions of Eastern Africa, the type-locality being t~inboni. It does not occur in the Victoria Nyanza, although mentioned ineidentallv by Bourguignat in his 'Espgees Nouv. Oukerdw6 & Tan~mika ' i 885, p. 7. Oceurrenee.--gxamples are found in Bed 16 in a greyish ~n&stone matrix, accompanied by opereula of A mpulla,ria, H~wa- eoid, Chelonian, and Croeodilian remains; a~in in Bed 1,6 ilt a greyish sandstone, associated with eoprolites, Chelonian and a Bull. Soe. Philom. Paris, ser. 9, vol. viii (1906) p. 275. 19r -~IR. R. ]3. _NEWTON ON _NO~'-M_KRINE MOLLUSC,~ [June ~9~4,

Crocodilian remains, and _4mpullaria; and also in Bed 2r in a greenish-grey ehy or marl. Localities.--Kachuku (Beds 16, 19, & 2r ; Nira (Bed 24) ; South Nim (Bed 2r Terrestrial Forms. Family Po_~tx'rIID~. TaoPiDol, uonx ~-u (E. A. Smith). (P1. XXX, fig. 14.) l~omatias nyasauus E. A. Smith, Proc. Zool. Soc. London, 1899, p. 591 & pl. xxxv, fig. 5. Ligatella n!lasanaW. Kobelt, Abhandl. Senckenberg. Natuff. Gesellsch. vol. xxxil (1909) p. 78. Tropidophora ngasana R. B. Newton, Q.J.G.S. vol. Ixvl (1910) p. 2~2 & pl. xviii, figs. 8-9. R e ma r k s.--The specimen here referred to differs only from the type in possessing fewer spiral costal, a variation which may be found to exist when one is dealing with several specimens. Such is really the ease in connexion with some Quaternary forms of the species from Nyasaland, which show well-separated and equi- (hstantly arranged costse. The species itself is not only related to Cyclostoma i~sulare of Pfeiffer from Natal, as pointed out by Mr. E. A. Snfith ; but there appear to be also some close affinities with C. letourneuxi Bourguignat and E. yon Martens's variety of the ~me, st~hlmanni, as well as with C. delmaresi Ancey, all of which have been well figured by E. yon Mal~ens in his ' Beschalte Weichthiere--Deutsch-Ost-Afrika' [MObius] 1898, vol. iv, pl. it, figs. 1, 2, & 5, pp. 4-6. Dr. Kobelt has recognized this species under the genus Ligatella of E. yon Mal%ens, the type of which is Miiller's Cyclostoma li.qatum, a smooth shell. Those shells there- fore, like that now under discussion, possess a prominently spiral ornamenhation (not present, however, on the two earliest whorls, which arc smooth as in recent examples of the species), and should more accurately be regarded as belonging to Troschel's TroTidophora of 1847, the type of which is ttm Cyclostoma cl~vieriauum Petit. 1 Distribution.--The species has been recorded from late post- Plioeene deposits near Lake Nyasa, 10eing also found living on the Nyasa plateau at Zomba. Only related forms [previously men- tioned] are known as existing in the Victoria Nyanza region. Oecurrenee.--From Bed 8, associated with .Limicolaria sp. and Ce• sp. L o e a 1 i t y.--Kikongo. Family A('IIATLXlD.E. ACITATI~-X sp. indef. (P1. XXX, fig. 12.) Remarks.--This genus is represented in the collection by a summit fragment only, which has a height and diameter of 1r and 10 millimetres respectively. It is of short conical form, and composed of five rather piano-convex whorls, including a smooth,

I Zeitschr. Malakozoo]. [Menke & Pfeiffer] 1847, p. 44. Vol. 7o.] REMAINS FItO~t THE VlCTOHI& ~'Y_.k~'Z.k REGION. 195 rounded, and obtuse apical region. There are some partly-preserved remnants of ornamentation, which appear to be quite characteristic of the genus, exhibiting a series of closely-set, in-egular, and longitudinally-oblique eostulations. It is probable that this fossil belonged to a species like A. l~anthera of F~russac, the well- known East African (Momba~, etc.) shell, which might have had dimensions such as 120 by 60 millimetres. Oecurrence.--The sl)eeimen is of solid limestone, and much mineralized at the base; it was obtained from 'pale green-~'ey clay' in Bed 2~, accompanying opercula of Amp,dlaria. :L o c a 1i t y.--Kachuku.

BL~I~TOX cf. ~ILOTIC:~ (Pfeiffer). (P1. XXX, fig. 13.) Bulimus nilotleus Pfeifl~r, Proe. Zool. Soe. London,1861, p. o~ (not figured~. Limlcolarla nilotlea Pfeiffer,' Novitates Coucholog.'vol. iv (1870~ pl. cx, figs. 1-3 &p. 5. Achatina niloticc~ Jickeli, ~Nova Aeta Acad. Cms. Leop.-Car. vol. xxxvii (1874) p. 151. 2~urtoa nilotica Bourguignat, ' Moll. Afrique I~quator.' 1889, p. 89 ; E.A. Smith, Proe. Malac. 8oc. London, vol. i (1895) p. 323. Livlnhacia nilotica E. yon M,~rtens, ' BeschalteWeichthiere Ost-Afrikas--Deutsch- Ost-Afrika' (K. MSblus) vol. iv (1898) text-figures, pp. 94-98 ; W. Kobelt, Abhandl. Senckenberg. Naturf. Gesellsch. vol. xxxii (1909) p. 69. Remarks.--The specimen referred to this form is supposed to represent the summit po~4ion of an individual that may have originally been S0 or more millimetres long. It is of helicoid appearance, and consists of fore" whorls which are steep and of piano- convex character; the apical region is smooth and obtuse, while the later whorls are ornamented with closely-set oblique eostulations of rather irregular and wa~ ~ design, crossed by obscure spiral striations. An obtuse medio-angulation surrounds the base, which would form the junction of the succeeding whorl. The sutm'e-line is well impressed, but slightly intelTupted by the thickened ends of the eostulatlons. The specimen is quite robust and solid, except at the basal surface, where the shell-structure becomes extremely thin and delicate, a feature most probably caused through protection by the covering of the next volution. No remains of the periostracum are preserved. Dimensions in millimetres : length =16; diameter =15. From its obtuse apical region and the peculiar characters of the sculpture, there is a great probability that the fossil belonged to a large Aclmtinoid shell, similar to Burtoa nilotica, a well-known species of Equatorial Africa, as has been suggested to the writer by Mr. E. A. Smith. It wa,~ this mollusc that Pfeiffer originally described and figured under Bulimus and gimicolaria respectively, and i~ was subsequently selected by Bom'guignat as the type of his genus ~urtoa, 1 a name which has about a month's priority of H. Ch-osse's genus Livinhacia, founded on the same t3-pe.~ Distribution.~Burtoa nilotica lives near the sources of the White Nile; as also in the region of the Victoria Nyanza, the x , Moll. Afrique ]~quator.' 1889, pp. 88, 89. Journ. Conchyl. vol. xxxvii (1889) p. 105. 196 MR. R. ]3. ~'EWrOS- OX NOX-MARIS"E ~OLZUSCA~ [June ~9t4,

coasts of Tanganyika, and in the country off the southern end of Lake Nyasa. 1 Occurrence.--At the basal fracture of the specimen the rock is observed to be a light-coloured, minutely-perforated, calcareous sandstone. It was obtained from Bed 21 in association with 2Lanistes and Chelonian remains. Locality.--Kachuku. LI~Ico~.t~I.t sp. indef. (P1. XXX, fig. 17.) R e in a r k s.--The collection contains two fragmentary examples of this genus, belonging to different individuals. One consists of a matrix-cast in which the four latest whorls have alone been preserved. This fossil, measuring 35 by 20 millimetres, is of oblong conico-tun'eted contour, and originally consisted of about seven volutions, the last being nearly three times the height of the penultimate; the presence of an elong~ate suboval aperture with a centrally-excavated columellar margin may also be noted. The second specimen represents a summit-region composed of five volutions, and measures 11 by 9 millimetres. It is furnished with a round, depressed, and smooth apex, the succeeding whorl being also smooth, while the third and fom~h whorls are relatively deep, compressed, and ornamented with numerous microscopical, fine, and slightly oblique striations; the basal whorl is compressed and sloping above, carinated at the centre, moderately inflated below, and has an obliquely striated sin-face like the previous whorls, but smooth below the carination; aperture oval (tinctured) and of small size. The relationships of such fragmentary specimens are, of course, difficult to trace, although they would appear to be, with Limi- colaria smitki Preston o a species of rather frequent occurrence on the plateau areas that border the Victoria Nyanza, Dr. Oswald having collected some recent specimens at Kisii. Occurrenee.--The summit-fragment was found in Bed 8, associated with Tropidoiphora, n~/ascmn and Cerast~es sp. ; the larger specimen came from Bed 31, aeeompanyingDinotherium and other vertebrates. Localities.~Nira (Bed 31) ; Ki,kongo (Bed 8).

Family BUI, IMINID~E. CE,~ASTt'S el. ~(ET~LE~I)O~rI Kobelt. (P1. XXX, figs. 15 & 16.) Cerastus ~n~ellendor2fflKobelt, Abhandl. Senckenberg.Naturf. Gesellseh.vol. xxxii (1909) pp. 15, 64 & pl. iii, figs. 11-15. Remarks.--The collection includes a fairly good matrix-cast of a for::: of Bulimini&e which belongs undoubtedly to the genus Cerastus of Albers (type=Buliminus distems Pfeiffer), and showing, moreover, certain resemblances to 6'. moellendo~:ffi from Shoa and Somaliland (East Africa). The specimen is small, of

1 E. A. Smith, Proe. Zool. Soe. London, 1893, p. 634. 2 Proc. Malac. Soc. London, vol. vii (1906) p. 89 & text-figure. Vol. 7o.~ RE.~[AL~'SFRO~[ ~E VICTORIA -~-YX~'Z.< ~EeIOX. 197 elon~outely conoidal form, and furnished with about six and a half whorls, the last being inflated and nearly double the length of the spire, whereas the spiral volutions are of plane-convex character. The apel~ure is suboval and of moderate proportions ; it possesses a rounded outer lip, an inner lip with a central indentation, from which proceeds a straight columella having behind a well-pro- nounced semicircular umbilical re,on. Whorls obliquely costulated. Dimensions in millimetres :- Aperture. Length ----15. Length---- 7. Diameter---- 10. Width = 5. In general contour, in the character of the basal cavity, the presence of the straight and prominent columella, and the costu- lated sculpture (obscurely preserved on the dorsal surface of the penultimate whorl), the specimen corresponds with the features of this species. Distribution.--Dr. Kobelt quotes Shoa in Abvssinla and Somaliland as areas where his species occurs. Oceurrence.--The specimen came from Bed 31 in the ' upper gravel zone,' and ' Close to the D/nofheri~tm jaw and other large bones.' It is of a light-colourcd marly appearance, with blackish mottling. Locality.--Kachuku. CERASTVS sp. indet. Rem~rks.--This specimen, with dimensions of 10 by 8 milli- metres, is of small conical shape, made up of five depressed whorls, which are nearly in the same plane. The Whorls are ornamented with a regular series of elevated and oblique costulations. i~r. E. A. Smith is of opinion that this fragment represents the summit-region of a shell like that characteristic of the genus Cerastus, which is probably its true inte13)retation, although it is quite flnpossible to suggest any particular species with which to associate the specimen. Occurrence.--From Bed 8, associate~l with TropiJophora nyasana and Limicol(~ria sp. Locality.--Kikongo.

EXPLANATION OF PLATE XXX. [All the specimens are in the British Museum (Natural History).] AMPULLARIA OVATX Olivier. (See p. 189.) Fig. 1. Dorsal view of the largest Sl)ecimen (natural cast). Nira (Bed 14). 2. Dorsal view of a medium-sized specimen, with the shell preserved. Nira (Bed 31). 3. Internal surface of a large isolated opercuhm, regarded as belonging to this species. 4. External view of the same specimen. Nira (Bed 14). LA,'qISTES CA~INATUS (Olivier). (See p. 190.) Fig. 5. Front view of large natural cast. Nira (Bed 14). Figs. 6 & 7. Two views of a smaller example with the shell preserved, and showing obscure spiral angulations. Nira (Bed 32). QUART. JOURN. GEOL. Soc. VOL. LXX, PL. XXX.

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MIOCENE MOLLUSCA-- VICTORIA NYANZA.

[ Fig{m~s ere of the 1~atJral sise , except whe:-e otherwise marked.] 198 MIOCENE OF THE IrICTORI& ~'YAXZA, ETC. [June 1914, CLEOPATRA EXARAT), (E. yon ~ffartens). (See p. 193.) Fig. 8. l~ront view of well-preserved testaceous specimen. 9. Magnified view of the same, showing the early ornamentation of the spire. Kachuku (Bed 19).

CLEOPATRA BULI~IOIDES (Olivier). (See p. 192.) Fig. 10. Front view of specimen. 11. Magnified view of the same, showing spiral sculpture on the n.~clear whorls. Nira (Bed 32). AC~ATII~A sp. indef. (See p. 194.) Fig. 12. Summit-fragment of individual with remains of sculpture striations. Kaehuku (Bed 24). ]3URTOA ef. NILOTICA (Pfeiffer). (See p. 195.) Fig. 13. View of a well-preserved summit showing a smooth and obtuse apex, the later whorls being ornamented with oblique costulations. Kachuku (Bed 21). TROPIDOPHORA NYASAI~A(E. A. Smith). (See p. 194.) Fig. 14. Front view of specimen, showing the rounded aperture and charac- teristic sculpture of the species. Kikongo (Bed 8). CERASTUS cf. ~LLENDORFFI Kobelt. (See p. 196.) Fig. 15. Front view of example showing aperture, etc. 16. Magnification of sculpture, obscurely preserved in the same specimen. Kachuku (Bed 31). LI~ICOLARIA sp. indef. (See p. 196.) Fig. 17. Front view of a fragmentary specimen showing the excavated colu- mella. Kachuku (Bed 31).

Disct-ssio~ - Dr. A. SMIT~ ~VoouwARD remarked on the interest of the Author's demonstration of the great antiquity of the Victoria Nvanza.~ The persistence of the species of non-marine mollusca since Lower Miocene times was especially notewolChy, even if their distribution had slightly changed. The PR~SID~n'T (Dr. A. STU~t~A~') observed some reluctance on the part of the Fellows to discuss a region which so few had been able to visit, bu~ he had been much impressed by the thoroughness of the work can.ied out by the Author in various branches of geology, and by ~he completeness with which he had illustlnted the ground by photographs taken under circumstances of exceptional difficulty. The AVT~OR hoped that his work oN the eastern coast of the Victoria Nyanza might result in a search being instituted for similar :Miocene deposits at the mouths of the other large rivers entering the lake; and he expressed his thanks to the President and to Dr. A. S. Woodward for their remarks, as also to the Fellows of the Society for their kind reception of his paper.