10 CARDIAL. 



some older specimens. The siphons are short, and but 

 slightly separated ; the branchial rather the largest, and 

 fringed at its orifice by about sixteen simple white cirrhi, 

 with minute yellow points at their bases. The anal orifice 

 has its inner margin uniformly plain, but there are below it 

 about twelve cirrhi, also red-dotted at their bases. The 

 sides of the tubes and the neighbouring part of the mantle 

 are dotted with scattered white filaments. Mr. Clark ob- 

 serves, that the tubes in a half-grown shell, of which the 

 transverse measure was an inch and a half, and the ventral 

 an inch and a quarter, were three-fourths of an inch in 

 length. The foot is cylindrical, finger-shaped, geniculated, 

 pale rose at the head, of a deeper red towards the middle 

 and extremity. It is at least twice as long as the shell. 

 " There are a pair of branchiae on each side of the body, of 

 the shape of segments of a circle, the upper one being as 

 long as the lower, but from its narrowness not half the 

 depth. They are pale-brown, conspicuously striated on 

 their outer surfaces ; less so within. The palpi are of the 

 same colour, and are very long, linear, slender, pointed, and 

 marked with raised transverse stria) on both surfaces. 11 — 

 Clark MSS. 



This generally-distributed species is one of our most com- 

 mon bivalves, and inhabits various depths of water, from 

 seven to eighty fathoms, all round our coasts. Muddy 

 ground, sandy mud, and muddy gravel, are its favou- 

 rite habitats. It is a solitary species or not truly gre- 

 garious, and is both brought up by the dredge from near 

 the coast, and taken by trawlers far out at sea. The shores 

 are sometimes, after stormy weather, strewed with its 

 valves. To enumerate its localities would be to name all 

 suitable places around our shores, for it is equally plentiful 

 in the northern and southern districts. 



