ARGIOPE. 21 



nately enabled to discover it seven years afterwards in a 

 living state. It may be easily distinguished from A. 

 decollata by its minute size and smooth surface, as well 

 as by its internal structure. It differs from A. Neapo- 

 litana in being only half the size and more convex, in 

 the foramen being much larger, and in the inside margin 

 of the upper valve being slightly and closely crenulated, 

 instead of having rather strong and distant tooth-like 

 notches, which is the case in A. Neapolitana. 



3. A. cap'sula"* JefFrevs. 



Terebratula capsida, Jeffr. in Ann. N. H. ser. 3, ii. p. 125, pi. v. f. 4, and 



iii. pi. ii. f. 7, 8. 



Body yellowish : peduncle rather long and slender. 



Shell nearly equivalve, oval or pouch-shaped, compressed 

 but rather higher towards the beak, glossy : sculpture, lines of 

 growth slight and remote ; tubercles as in the last species : 

 colour yellowish- brown : margins rounded at the sides and in 

 front, almost straight behind, giving that part the appearance 

 of being auricled : beak slightly prominent, its point separated 

 by the hinge-area : foramen triangular, but not disproportion- 

 ately large, occupying about two-thirds of the dorsal space : 

 deltidium imperceptible : hinge-plate, teeth, and sockets as in the 

 last species: skeleton undeveloped, and septa wantiug. L. 0*03. 

 B. 0-02. 



Habitat: 18-25 fathoms, Plymouth (Norman, from 

 Webster) ; Guernsey (Lukis) j Dublin Bay, and off Port- 

 rush (Waller); and Lame, co. Antrim (Hyndman & 

 J. G. J). It occurs with A. cistelhda, nestling in the 

 hollows of old shells of Pectunculus glycymeris and 

 other bivalves, frequently among clusters of Lepralice, 

 I have found it also at Etretat in Normandv on stones 

 which had been taken up in trawl-nets at a distance of 

 about four leagues from land. 



* A little box. 



