130 GASTROCHJiNA. 



more the appearance of a Saxicava than of a specimen of this 

 genus; but the large hiatus characterises it as a Gastro= 

 chsena. 



22. cucuLLATA, p. 14, Deskayes. — Crassa, cuneiformis, 

 postice maximo inflata, ad terminum vix acuminata, autice 

 angusta, acuminata ; hiatu maximo ; margine ventrali intus 

 crasso, complanato ; cardine dentibus tumidis. — Very thick 

 and wedge-shapedj with a broad thickened margin. 



23. TRDNCATA, f. 13, Sowevby. — Subrugosa, epidermide 

 fusca induta ; latere antico attenuato ; latere postico late 

 truncate. This large species is broadly square at the posterior 

 end, and narrow and pointed in front. 



24. LAGENULA, f. 18, Lcvmarck. — Parva arcuata tenuis, 

 postice truncata, sulcata, antice subacuminata, tuba bulbi- 

 formi, quasi articulata.— Small thin arched valves truncated 

 at the end. The tube has the appearance of being partly 

 coiled or jointed. 



25. PUPiNA, f. 16, Deshayes. — Valvis ignotis. Tuba in 

 sectiones divisa, per latus adhserens. — The valves are un- 

 known, the tube is flask-shaped and divided into five sections. 

 It adheres to flat surfaces of shells. 



Species truncated, with a keel on the dorsal area. 



26. ROSTRATA, f. 11. — Ovato-oblouga, subtortua, epidermide 

 fusco induta, latere antico ante umbones producto, rotundo, 

 hiatu maximo ; latere postico undulatim truncato, oblique 

 carinato ; margine dorsali in aream planulatam elevato ; 

 margine ventrali convexo ventricosa. — This and the three 

 following species are characterised by a keel dividing the 

 posterior part of the shell. G. rostrata is strongly wrinkled, 

 and its outlines are tortuous. The dorsal area is distinct, 

 flattened, and raised at the margin. 



27. Eetzii, f. 10, Deshayes. — 0. rostratw similis, hand 

 tantum tortua, sulcis baud tantum conspicuis ; margine 

 dorsali vix elevato, margine ventrali magis convexa. — Not so 

 deeply grooved nor so tortuous as G. rostrata, with straighter 

 dorsal and more prominent ventral lines. 



