ON CEPMALOPODAFROM THE WXTE RELLO ISLANDS. 677

38. t 'cplialopoda I'rotii the Monte 13ello Islands. By G. C:. ROBSON,H.A.*

LHeceired March 18, 1914 : Read June 9, 1914.l (Trxt,-figure 1.) Isncx. Stract.ure : l'age Rndnla, maurlihlen, hectocotjliis of Sepiadnriim arritum, up. n...... 878, 680 \'ariatioil, &c. : I)ifl'erc!nces beta eel1 Spyiadorium and Sepioloidea summarixeil ...... 875 *\'e hdarium nzcriticm, rp. n., intnoiedintr betawti .8rpiadurium nnd Sepioloidea ...... ti77 C;eogrnptricd Zodopy : 1)istril)utioii of SepiuduTium anritwm, Irrubnlily nnolnalons ...... 67X Syhtematic : Sepindarizina awitriin, sp. 11...... ti7X

Of tlie two of Cephalopoda obtained by Mr. P. 1). MontiLgue from the Monte Bello Islands, one specimen is of considerable interest--a, Myopsid which has been referred after. some hesitation to Sepiadarium. The differences between the latter and the closely-allied #epioloidea, though they have been touched upon by sever:tl authors, have not been fully summarized as yet. The following table gives the more important differences :- Sepiadarium Steenstrup. ,Y'cpioloidea d'Orb. 1. Funnel attached to mantle by a . , . . by cartilagiiiouri plugs of the ligament (1)(2). mantle that tit into sockets ou the funnel (1) (2). 2. Ventral poreri absent (2). ....prenent (2). 3. Mantle fringe absent (2). .... present (2). 4. Fins short (4). .... long (4). 5. Tlie heotocotylised arm bearing Suckers of the hcctoc:otylux per- on its distal half a series of xiNting as small papillilla: ; the arm trsnsverHe ridges, which are the grooved diagonally on itr imrw laterally produced peduncles of aide (4). the suckers (4).

In respect of Nos. 1, 2, 3, ant1 5 ill the almve list, the form here described is referable to rSepiacla,rium. The length of the fins, on the other hand, suggest,s affinity with Kepioloidea. It is not desirable on such slender grounds, however, to create a new genus intermediate hetween the two forms under discussion for. the reception of this species. Rut it is certain that in tlie present state of our knowledge we Itre entitled to regard this as an unusual form of ~'iepiailccrium,,intermediate in respect of one character between that, genus and ,Y'cpiolOi(7e~~

Comniuuicatecl lry Prof. J. STAXLETGAIII)INER. MA.. V.11.S.. F.Z.S.. and yublislird by pwiuihsioii of !lie 'I'rustees of tlic Ihitiili h1uwiIii. 678 MR. G. C. ROBS08 ON CEPIIALOPODA Up to the preseiit Sepioloidea appears to be regnrtled as tlie Austn~lianform of the two Bepiadarian genera, wliile Sepiic- dariuna is considered the Pacific form. We now find that the latter extends its range to W. Australia, thougli not by a typical member of the genus. Whether, in the first instance, the distinction of the two forms into Pacific and Australian rested upon secure and sufficient evidence we carinot say as yet. If the investigntion of the f:iunas of these arens upholds this distiiiction, the interest and importance of this species of ASepiadccrizLm with rC~~ioloidea-char;~cters,r?s occurring in the distributional area of tlie other genus, will he increased. The structure of the hect,ocotyIus corresponds closely with that described by Brock (5) for ~Sepirwlarimz. It should be observed that the series of transverse ridges or bars (hock’s “ Quer- balken”) are of such a shape as to suggest the ohvious con- clusion that they represent the fusetl bases of the pairs of suckers, a proxirnal merriher of the morpliologically posterior row being f wed with a divtsl member of the inorpliologically anterior row.

I. SEPIADARIUMAURITUM, sp. n. (Text-fig. 1.) External appenmmce.-The a.nininl is sni;L11 and sqixit, the width of the niaiitle area being about eqiin.1 to its length. The fins are rather long and ear-sliapetl, tlie inferior p~rt~ioiibeing slightly tiroader than the superior. The rnaiitle-irist~rtioria,t the neck is tolerably broad, while posteriorly the edge of the inantle exhibits a very slight concavity. There is a very feebly developed interbr:ichial mernbrme. On the arms the suckers are a.rrxnged in two alternating rows, mve :It the distal third, where they become abruptly smiller ailtl more irrngii1:trly disposed. The teritnci11:ir amis are provitletl with a short rnenibrane conterminous with tlie area occripind hy the suckers. The colour (formfi.lin-prcser\’etl specimen) is tlnll grey, covered 011 the t1ors:tl mrfitce by nnmerons sni:~ll round ptclies of pile retl or brown :md fine black or d:irk-lrown spot,s. Only the hthrare continued 011to the vcntrd surface and the a.i~nis. The pitches and spot& are found, tlioiigli inore spusely, upon the fins. For c1i:ir:icter of tlie hectocotylized arm, 0. text-fig. 1, C. I)iniei/siol~s:- Mantle, max. length ...... 11.25 mm. ,, max. breadth ...... 12.5 ,, Length of fins ...... 8.75 ,, Total length (from a to interbrachial meinbrane of the ventral arms) ...... Length of arms : 1st pair ...... 7 ,, 2nd ,, ...... 6.8 ,, 3rd ,, ...... 9 ,! 4th ,, ...... 7 ,, PROM THE MONTE RELLO ISLANDS. 679

8epiaclaiiunt uuriturn.

A. Ihrdview. x 2 : a, outline of fin. II. Attacliriirrit of fullrid to tuicntle. x 2. (’. IIectocotylus. X 6. I). Mai~dibleu. x 12. E. Badula. 4 oc. x 6 obj. 680 OW CEPRALOPODA FROM TUE MONTE BELL0 ISLASDS. Interm1 churnctws. --The ntandibles (text-fig. 1, D). The rudula (text-fig. 1, E) resembles that of 5'. kochii figured by Appellof (3) pretty closely ; but differs in the condition of the basal plate of the median tooth, which is much deeper and of p different shape, in certain characters of the lateral tooth and of the inferior marginal. It is unfortunately impossible to give a fuller account of the internal characters, owing to the fact that only one specimen is avails.ble for examination. Locality. Dredged OR Hermite I. (Monte Bello Islands), U'. Aiistraliu. Type in the Hritish Museum (Zoological Department).

2. P0LYPG.S sp. Two specimens from the same station (one immature). This form, which might be referable to more than one Pacific species, cannot be satisfactorily identified.

Literature refirred to. 1. JOUBIN,L. Mem. Soc. Zool. France, xv. 1902, p. 81. 2. STEENSTRIJP,J. K. Danske Vidensk. Selsk. Skrift., 6 Raekke, 1881, p. 414. 3. APPELLGF,A. Abh. Senckenb. Naturf. Ges., Bd. xxiv. 1898, p. 561. 4. PELSENEEEL,P. Lankeater's Treatise of Zoology. . 5. BKOCK,J. Zeitschrift fur wiss. Zool. xl. 1884, p. 105.