﻿GASTROCmENA.— Plate IV. 



The larger concentric ridges are a little distant, 

 and the intervals are filled up with smaller raised 

 stria?. 



Species 27. (Miis. Brit.) 



Gastrqiih.bna TliNEKA. Gas. icda temussimd, elonr/atd, 

 nihjvyl'l^ ruiiq'rrs:;i1, tm iii,-isiliie .^friat'!, moclioli- 

 fimni, /M,^'/ //,,',///-,„ nhlnpir ri.i- cii^pirih- sulcata; 

 'hiatn ,:,,i.,,i^lin,ri,ln^ ,'loi,,,nto. 



The thin Gastrochjjna. Shell very thin, elongated, 

 narrow, compressed, very finely striated, shaped 

 like a modiola, with scarcely conspicuous oblique 

 sulcus ; hiatus very narrow, elongated. 



Deshayes. Proc. Zool. Soc. 1854, p. 32". 



Hah. Philippine Islands. 



Species 2k. (Mus. Brit.) 



Gastroch^na inteerhpta. Gas. tesid n,i,jiiM,l. /■.■,-. 

 tiusculd, elmiffotd, siihdepressd, trnin.<.^iiii,!. I<rri- 

 gaid; area posticd elevatd, sidci^ rniicrnlririg 

 tribus vel quatuor divisd; hialii eloiifjato-ocald, 

 postice ahrupte iermwanti. 



The interrupted Gastrochjina. Shell narrow, 

 rather straight, elongated, rather depressed, vei-y 

 thin, smooth ; posterior area raised ; divided by 



three or four grooves ; hiatus elongate-oval, 



posteriorly abruptly terminating. 

 Deshaye.s. Proc. Zool. Soc. 1S54, p. 32(>. 

 Hab. Philippine Islands. 



The valves of this species resemble those of Gas- 

 trochceiia lagenula, but are very much more arched. 

 The grooves, by which the posterior area is divided 

 into a series of tablets, have probably, in the latter 

 species, some connection with the exterior partitions 

 of the tube. "We have not the tube of the present 

 species, bat believe it will prove to belong to the same 

 group. 



Species 29. (Mus. Brit.) 



GaSTROCHSNA MACROCHISMA. Gas. te><ht (!<;-.c/.«/»'(/, 



inflatd, rotundato-cuneiformi, tenuUer strintd; 

 latere antico ante umbones produdo, yiihani- 

 minato ; latere posiico latissimo, ad terutiiunii 

 subrutundo, margine dorsali declivi; hiatii lati.^-- 

 simo, breviiisculo. 



The wide-oapino Gastrochj:na. Shell very short, 

 inflated, roundly cuneiform, finely striated ; an- 

 terior side produced in front of the umbones, 

 rather acuminated ; posterior side very broad, 

 rather rounded at the end, dorsal margin sloped; 

 hiatus very wide, rather short. 



Deshayes. Proc. Zool. Soc. 1854, p. 326. 



Hab. Philippine Islands. 



