MARINE MOLLUSCA OP THE IGNITED 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 striae. 



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. PSITTACEA, 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 LINGULIDJ3. 



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 laminae, diverging from 



