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 PLICATULA, Lamarck. 
Syst. An., 132. 1801. 
1. P. RaAMosA, Lamarck. Fig. 547. 
Anim. sans Vert., vi. 6. 1819. 
Shell oblong-triangular, very stout and solid, with numerous 
large, ramified foids. White, with ferruginous markings. 
Length 1 inch. 
North Carolina, southwards. 
Crass 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 ; dicecious 
in all the genera? reproducing by ova only. 
Family TEREBRATULID. 
Shell rounded or oval; larger yalve 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. 
