198 AMERICAN MARINE CONCHOLOGY. 



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



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



This beautiful little European species has been found at Sable 

 Island, and will possibly be detected in our northern waters. 



Genus PLICATTTLA, Lamarck. 

 Syst. An., 132. 1801. 



1. P. RAMOSA, Lamarck. Fig. 541. 



Anim. sans Vert., vi. 6. 1819. 



Shell oblong-triangular, very stout and solid, with 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 bilaterally 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, variously 

 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 by direct contact of sea-water 

 with the vascular tissues of the brachia and mantle lobes ; dioecious 

 in all the genera? reproducing by ova only. 



Family TEREBRATULIDJE. 



Shell rounded or oval ; larger valve prominently beaked, smaller 

 one provided internally with a shelly loop to which the brachia 

 are attached. Valves articulated by two teeth in one valve 

 received into sockets in the other. 



