CORBULA. 55 



minent as in that species. The young of Loch Fyne 

 specimens are proportionally more slender than the 

 adult_, and more elongated in the line of the major axis ; 

 but they essentially differ from N. rostrata of the same 

 age or size. A valve which I dredged in deep water off 

 the east coast of Shetland is nearly an inch broad^, and 

 coarsely wrinkled : it agrees with specimens which I 

 examined in the Museum at Christiania, described by 

 Sars as N. arctica, as well as with some dredged by 

 Torell in the Arctic Sea. 



Brown called the present species Anatina brevirostris 

 and Thracia brevirostris, and Nardo Cuspidaria typica. 



Genus III. COR'BULA^, Bruguiere. PI. II. f. 5. 



Body oval, rather thick : tubes seldom protruded ; orifices 

 fringed : gills 2 on each side, unequal-sized : pal2:)s corre- 

 sponding with the gills in number and position, but equal in 

 size : foot tongue-shaped and thick. 



Shell oval, nearly equilateral, rather solid ; posterior side 

 wedge-shaped : teeth, a short and strong cardinal in each valve, 

 and a ridge-like lateral on both sides of the right valve. 



The structure of the shell is like that of the Anati- 

 nid(B : according to Carpenter ^' the outer layer is com- 

 posed of large fusiform cells^ whilst the inner is nearly 

 homogeneous/^ S carles Wood informs us that fossil 

 species have been found as early as in the lower Oolite. 



Miihlfeldt caUed this genus Aloides ; and modern 

 systematists have invented for it other equally ill- 

 compounded names^ such as Spenser^ in his ^ Teares of 

 the Muses/^ designates 



" Heapes of huge words uphoorded hideously, 

 With horrid sound though having little sence." 



* A little basket. 



