198 AMERICAN MARINE CONCHOLOGY. 



3. L. SULCULUS, Leach. Figs. 545, 546. 



Forbes and Ilanley, Brit. Moll., t. 53, f. 4, 5. 

 This beautiful little European species has been found at Sable 

 Island, and will possibl}^ be detected in our northern Avaters. 



Genus PLICATTJLA, Lamarck. 

 Syst. An., 183. 1801. 



1. P. RAMOSA, Lamarck. Fig. 547. 

 Anim. saus Vert., vi. 6. 1819. 

 Shell oblong-triangular, ver^^ stout and solid, vvitli numerous 

 large, ramified folds. White, with ferruginous markings. 

 Length 1 inch. 



North Carolina, southwards. 



Class BRACHIOPODA. 



Animals provided with a shelly covering composed of two 

 valves, each of which is Inlaterally symmetrical, and to which it 

 is organically attached by three principal pairs of muscles. Soft 

 parts also bilaterally symmetrical, consisting essentially^ of a 

 mantle composed of two lobes, to which the valves correspond, of 

 which lobes the outer edges are disunited throughout the greater 

 part, or the whole of their extent ; a disk and membrane, variousl}^ 

 modified in form, with its edges fringed with a series of tubular 

 brachia; the mouth situated within this disk at its posterior 

 portion. Respiration performed b}- direct contact of sea-water 

 with the vascular tissues of the brachia and mantle lobes ; dicx^cious 

 in all the genera? reproducing b}' ova onl}-. 



Family TEREBRATULID.E. 



Shell rounded or oval ; larger valve promincntl}^ beaked, smaller 

 one provided internall}' with a shelly loop to which the Virachia 

 are attached. Valves articulated by two teeth in one valve 

 received into sockets in the other. 



