142 INVERTEBRATA OF MASSACHUSETTS. 



the coast of Maine. Its usual residence is in more northern 

 seas. 



An examination of the descriptions of T. caput-serpentis, given by 

 Linnaeus, Miiller, and Chemnitz, and a comparison of them with our 

 shell, had well satisfied me of their correspondence. The downy epi- 

 dermis is a character too singular to be often found, or to be over- 

 looked. This, however, is rubbed off very easily. No account of 

 the internal bony processes is given in any description except that by 

 Mr. Couthouy. These would afford the best possible specific charac- 

 ter, were it not that they are usually more or less broken. But I have 

 been relieved from all further speculation by the receipt of specimens 

 from Dr. Loven, which settle the identity of our species with the Eu- 

 ropean caput-serpentis. Deshayes conjectures, probably with justice, 

 that the Anomia aurita of Gmelin is the same thing ; and also that 

 Anbmia pubescens of the same author and others is this shell in a 

 young stage, when plentifully coated with pubescence. T. costata, 

 described and figured by Lowe, in the " Zoological Journal," ii. 105, 

 pi. 5, f. 8, 9, is very closely allied ; but it is a smaller, more solid 

 shell, with fewer ribs, and entirely different internal processes. 



TEREBRATULA PSITTACEA. 



Shell sub-triangular ; narrowed above, the beak produced into 

 a decurved horn ; surface striated, foramen triangular. 



FIGURE 91. 

 State Coll., No. 144. Soc. Cab., No. 2349. 



Terebratula psittacea, GMELIN ; Syst., 3348. CHEMN. ; Conch., viii. 78, f. 713. 

 DESHAYES ; Encyc. Mtth., Vers, iii. 1025, pi. 244, f. 3, a, b, c. LAM. ; Jin. sans 

 Vert., vii. 333. LISTER; Conch., 211, 46. DILLWYN ; CataL, 296. TURTON ; 

 Brit. Biv., 236. Conch. Diet., 5, f. 12 to 14. 



Shell thin and fragile, brownish-black or sea-green, of an in- 

 flated, triangular form, one of the valves produced into a long, 

 pointed and strongly curved beak, something like a parrot's beak ; 

 along this runs a triangular channel, (formed by the inflected mar- 

 gins,) the third side of which is completed by the tip of the other 

 valve ; the smaller valve is obovate or fan-shaped, about two 

 thirds the length of the longer valve ; surface marked with con- 

 centric lines of growth, and with numerous, fine, diverging striae, 



