46 



Solen, Miictm s;icliiliiieii8w, Ttlliii;i iinüntn, to tin- liiicinu iiii»! DiplodoiiU, umt 

 abovd al! tu tht' l>i>.siiiiii', yet liy lu» inraiis üinuil 



Nxrula ColiboUUv S.iworl.y. l'i. VI, f. 2S an.l 28 u, 



(Min. Com-li. j.l. 180. f. 2. 1S|8 -Lyell, Kinn ..f (J.-..1 ],. 'iitl», f II.}, 



in thi- 2tMl c.l. lS4l.-VV.>o(l CniR Moll IF, p. 8-i, |.l 10, f 9, uihI 



suppl. p. m, j.l 10. r 2.-\V«K«lw!»r.l M.imiiil ..f M.,11. pl 17. f. 1.8 — Syii. 



N. niir.iliilijj Hiiuls. .Xdiinis uinl lU-cvo.- Sy?i. also N. insij^nii« (loiilil, 

 Otirt Concli, \y I7.">. Syn. also N l/vulli n<'!l. .\mi. ami Mn;; Nat. Hist, 

 1871,? cett». 



Tlieiv CJiM l>e no donht tiliotjl tliu fiwt. tliat flu; .Ia]>aiirsc Niiciilaj fif tlie 

 type of N. G)lilHildia' (^nns Acila) have only lictn scpiimtod in con.st-iiiipncc of 

 so few spei-iniens liavinj; Ix"«'» examinetl. The li>c;ilitii>s in vvliii-li this sliell i« 

 fotnul fossil, supplying to n great extent this want, tlie iilcntilicalioii, so inneh 

 (loubtetl and (dyected to l>y the author of the highly vtiliialile monograph on the 

 Crag- Mollusca, becomes unavoidable. The specimens foimd at Oji, tolerably 

 munerous and well j)reserved, answer, on the wholf, t4) (iould's diagnosis and 

 description as well as to the ligure given of N. inirabilis. Aecording to Itonld 

 himself, N. insignis is almost identieil with tlii.'» shell, and it ditfers only in two 

 trifling points, viz., the angle formed by the iuftMior margin witli the smaller, 

 straight side margin (an angle very VHri^d)le in the different sp'rinv.iisl. and in 

 the angular markings at the extremities, whicli app.'ar in Hinil's ligua-, and 

 which sonietimeR, but not often, are also seen in flu- Oji 8|K?cimcn8. ihx tlie 

 other hand, there is iio difference whatever froni the true N. (-'oblMildiie. 

 Especi.ally the larger sixvimens found not at Oji, but at Shinagawa. Kanagawa, 

 Yokohama and in the province of ^lino— s|K'cimen8 to which liowever some of the 

 Oji S|>ecimen8 approximate— arc jierfeetly similar to the larger s|KHimen8 of N. 

 Coblx)ldi;e. The posterior part ((iould's anterior one I is elongated, uauide«! at 

 the extremity ; the anterior one (<io)ild"s jioslerior side) !.•* truncated, often con- 

 cave, sometimes provided with a prominent rounded k«il : and «omel inn's next 

 to tliis keel, there is in some s|iecimens even a »light furrow which mikes the 

 angle appear still sharper. As for the sculpture. I dare 8;iy that the zig/Jig lines, 

 ilivergiiig from the centnil axis of the side-ffu-e, always cover either the whole 

 surface or at least the greater jwrt of it. In this resjioot, iiideetj un im|»ortant 

 objection to the identificsition would lie the remark of Wood (in his supplement) 

 aUiiit a smooth l>elt in very large C-'r.ig-siiecimcn.«, if 1 had not succeeded in 

 limling it also in some of the Kanagawa and Shinagawa s|)ecimcns. I figure it, 

 fragmentary as the sj)ccimen is, and may adil that indiiiitions of this lielt aro not 

 unfreipient in other s|R-eimenR. For instance one more of tlie Mino specimens 

 h;is a di.-tinct belt on the anterior and posterior side (es|x'< ially the latterl and 

 wufdd show it most likely entirely, if the centml |Mirtion was not fnicture«!. 

 Another Kanfigiiwa specimen has a rather broad Wit (2 mm. I liehind. but it is 

 smaller in the auterior p.»rt of the shell. This 8|)ecitnen has only 27 mm. in 



