A. E. Verrill — Mollusca of the New England Coast. 261 



shells, but concentrically lined in the young. The surface is else- 

 where covered with pretty regular and not very close, slightly 

 elevated concentric lamellfe, which are sometimes more or less 

 rellexed at the anterior end, while on the posterior dorsal area they 

 are thin, more elevated, nearly straight and divergent. There is no 

 distinctly defined lunular area, nor any definite radiating ridges 

 running from the beak to the anterior margin, though a very indis- 

 tinct undulation may sometimes be detected. The ventral margin is 

 pretty regularly curved and shows no indentation below the acute 

 posterior tip. 



Amussium, sp. 



Amussium fenestratum Verrill, these Transactions, vol. v, p. 582 (non Forbes). 

 ]Mr. W. H. Dall has called my attention to the fact that the Amer- 

 ican specimens formerly referred by me to the species quoted are 

 specifically distinct from the European types. I have been able to 

 confirm this opinion by direct comparison of our shell with typical 

 specimens sent to me by the Marquis de Monterosato. Our shell 

 has a peculiar transverse striation on the hinge-margin not seen in 

 the European specimens, and not more than two internal ribs, one on 

 each side. The sculpture, also, is finer. 



Pecten puStulOSUS YerriU. 



Peden Hoskynsi and yar. pus tulosics Verrill, these Transactions, vol. v, p. 581, pi. 42, 

 figs. 22, 22a ; pi. 44, fig. 11 {7ion P. Hoskynsi Forbes). 



By Mr. W. H. Dall, who has made a special study of the shells of 

 this group, our American species is believed to be distinct from the 

 typical Mediterranean form, with which he has been able to compare 

 them directly. Although they are closely similar in form and exter- 

 nal sculpture, our specimens difier in the hinge and in the absence of 

 internal radiating ribs, characteristic of the genus Amussitim, and 

 which are present in the true A. Hoskynsi. 



Possibly P. imhrifer Loven may be identical with P. piistulosus, 

 and not with A. Hoskynsi, to which it has been referred. In that 

 case Loven's name would have priority. 



Pecten Clintonius Say. 



Pecten Clintonius Say, Journ. Acad. Nat. Sci. Phil., iv, p. 124, 1824, pi. 9, fig. 2. 

 Pecten tenuicostatus Mighels, Proc. Bost. Soc. Nat. Hist., i, p. 49, 1841 (young). 

 Pecten principoides Emmonds, Report N. C. Geol. Survey, 1858, p. 280, fig. 198. 



A comparison of specimens of this Miocene species, from Surrey, 

 Va., with the more strongly ribbed, deep-water form hitherto 



