Qapers, Piddocks, and Ship-worms i 5 i 



Basket-shell 



Interior of Basket- 

 shell, showing 

 hinge-teeth 



yellow and brown, ornamented by concentric ribs 

 in the riglit valve, but these become mere raised 

 lines in the left. The hinge-teetli in 

 the right valve consist of a thick, 

 curved cardinal, flanked by a ridge- 

 like lateral on either side ; in the left 

 valve the cardinal is hollowed to take 

 the cartilage, and beside it is a cavity 

 to fit the cardinal of the right. The animal has a 

 comparatively large and thick foot, which it uses 

 for burrowing just below the surface 

 of sandy and gravelly sliores, from 

 extreme low water to about 70 fathoms. 

 There are, however, other Basket- 

 shells beside those of the genus Corhida, 

 of which the subjoined figure of the 

 Pointed Basket-shell {Nccura citsjndata) 

 will serve as a ty^e. In this genus, of which we 

 have three species, the shells are tliin, fig-shaped, 

 and with unequal valves, though the 

 disparity is not here so great as in 

 Corhula. The siphons are longer, 

 and the hinder part of the shell is 

 drawn out to partially cover them ; 



their orifices are protected by long 

 tentacles whose ends are divided into 

 several finger-like points. 



The Pointed Basket-shell (N. cusjn- 

 daUi) is much drawn out behind, 

 tolerably solid, — more so than in the 

 other species, — much swollen, and the 

 left valve larger than the right. Its colour beneath 

 the red-brown epidermis is whitish. The horn- 



Pointed Basket-shell 



Siphons of Nerera 

 (enlarged) 



