MARINE MOLLUSCA OF THE UNITED STATES. 199 
Genus TEREBRATULINA, Orb. 
Comp. Rend., xxv. 268. 1847. 
1. T. SEPTENTRIONALIS, Couthouy. Figs. 548, 549. 
(Terebratula.) Bost. Journ. Nat. Hist., ii. 65, t. 3, f. 18. 
Terebratula caput-serpentis, Gould (non Auct.), Invert. Mass., edit. i. 141. 
1841. 
Shell obovate, whitish or yellowish-white, thin, translucent; upper 
valve truncated horizontally at the apex; foramen large, one side 
completed by the apex of the lower valve; surface covered by 
minute radiating strize. 
Length 15, width 12 mill. 
Maine, northwards. 
Family RHYNCHONELLID. 
Shell with radiating ribs, the arm supports long, slender, simple, 
and gently curving towards each other; no area; the opening for 
the pedicle usually completed by two small pieces; animal with 
elongated spiral arms. 
Genus RHYNCHONELLA, Fischer. 
Mem. Soc. Imp., Moscow, ii. 1809. 
1. R. psirracea, Gmelin. Fig. 550. 
(Anomia.) Syst. Nat., 3348. 1790. 
Shell subtriangular, thin, inflated, brownish or greenish; beak 
produced and curved; surface radiately finely striated. The 
internal processes consist of two slender curved parallel prongs 
proceeding from the base of the teeth of the upper valves. 
Length 12, width 8 mill. 
Newfoundland, northwards. 
Family LINGULID. 
Shell pedunculate, peduncle passing between the valves; inar- 
ticulate, subequivalve ; brachia unsupported by calcified processes. 
Genus GLOTTIDIA, Dall. 
Am. Journ. Conch., vi. 157. 1871. 
Shell linguiform, smooth, elongated; neural valve furnished 
internally with two sharp narrow incurved lamine, diverging from 
