434 TAPESINiE. 



Sub-fain. TAPESIN.E. 



Siphons free at their extremities. Foot lanceolate, bys- 

 siferous. 



Shell oblong, transverse. Hinge with the cardinal teeth 

 compressed; lateral teeth single, or none. 



Genus TAPES, Megerle von Miihlfeldt. 



Siphons united as far as the middle, diverging at their 

 ends ; branchial siphon crowned with arborescent tentacles ; 

 anal siphon ending in simple, cylindrical tentacles ; mantle- 

 margin simple. 



Shell transversely ovate, inequilateral, closed ; margins 

 entire. Hinge tri-dentate, teeth sometimes diverging, some- 

 times approximate, sub -parallel, often bifid or canaliculate 

 at the apex. Pallia] impression deeply sinuated posteriorly ; 

 sinus semi-oval, somewhat horizontal. 



Syn. Paphia, Bolt., not Lam. 



Ex. T. pullastra, Montagu, pi. 109, fig. 2. Shell, T. 

 literata, Rumpkius, fig. 2, a, 2, b. 



The animal of Tapes is laterally compressed and trans- 

 versely ovate ; the margins of the mantle-lobes are simple 

 and entire, and the siphons have both their orifices bor- 

 dered by cirrhi, which in the branchial are ciliated ; the 

 labial palps are triangular and sub-equilateral ; the gills 

 are wide, sub-quadrate, unequal, and posteriorly united ; 

 and the foot is large, compressed, linguiform, and furnished 

 at the base with a byssal groove. The hinder end of the 

 shell is always the longest, the surface of the valves is 

 smooth or transversely striated, the inner margins are 



