CONCHYLIA— />rT/frJ«J. 51. 235 



Shell about a quarter of an inch in diameter, whitish, with the 

 beak terminal : the under valve has the perforation entire all 

 round, and produced into a raised cylindrical tube. The plug 

 of attachment is tendinous. 



51. TEB.EliB.XTLL\—BRlGllERE. 



Testa ovaia, intpquivalvis, pedicello tendineo fixa ; ralvd su- 

 periori timbone producto,perforato sen emargiiiato ; inferior i 

 ramis duobus, Sfepe ramu/osis, e disco infer nu protensis. 

 Cardo denfibus diiobns : lateralibus iitdlis. hiyamentiua 

 interiintn. 



Shell oval, inequivalve, fixed by a tendinous pedicle ; the upper 

 valve with the beak produced, and perforated or emarginate ; 

 the under valve with two elongated projections issuing from 

 the internal disk, and whicii are sometimes variously branched 

 Hinge with two teeth : lateral teeth none. Ligament internal. 



This genus is also parasitical, being fixed to submarine sub- 

 stances by a tougii sliort stalk, wliich issues from the aperture at 

 the termination of the extended beak in the upper valve. Tlie 

 internal structure of the under valve, independently of the strong 

 joint-like primary teetli, exhibits a remarkable apparatus for 



2h 2 



