NO. 1177. NORTH AMERICAN LEPTONACEA—DALL. 887 



low, valves compressed, very inequilateral, the bealcs being- nearly at 

 the posterior fifth ot the shell; left anterior lamina Aery long, rather 

 elevated, with a very small hook, posterior lamina short, nearly obso- 

 lete, with an elongated resiliary pit below it; adductor scars small, 

 high up, the anterior narrower, the posterior rounder;' pallial scar 

 linear ; surface polished, smooth, or marked only by incremental lines and 

 very obscure occasional radial striulations. Lou. 5, alt. 2.8, diam. 1 mm, 

 A single left valve was dredged in 22 fathoms off Cape Lookout, 

 North Carolina, on sandy bottom, with a temperature of 7S.2o F., by 

 the TJ. S. Fish Commission. 



ERYCINA FERNANDINA Ball. 



Erycina ? fernandina, new species. 



(Plate LXXXVIII, fig. 6.) 



A. 12. Shell small, ovate, pellucid white, sometimes with irregular 

 radial opaque white narrow streaks; moderately convex, with a very 

 thin, pale straw-colored epidermis; very inequilateral, the j)osterior side 

 short; beaks distinct, the prodissoconch often consjjicuous ; surface 

 polished, sculptured only with faint incremental lines and obscure, 

 irregular microscopic radial stride; right valve with the anterior and 

 posterior lamelhe short and strong, with a marked sulcus above each of 

 them, the anterior with a conspicuous hook; resilium well developed, 

 but short; adductor scars small, narrow, pallial scar linear. Lon. 3.75, 

 alt. 2.8, diam. 1.5 mm. 



Dredged oft' Fernandina, Florida, in 294 fathoms, coral sand, by the 

 U. S. Fish Commission, bottom temperature 4G° F. The strong lamiu;e 

 and the deep sulci above them give this species, when casually observed, 

 the look of a Mysella. 



ERYCINA (PSEUDOPYTHINA) RUGIFERA Carpenter. 



Pythina rugifera Carpenter, Suppl. Kept. Brit. Assoc., 1863 (1864), pp. 602, 643; 



Proc. Acad. Nat. Sci., Phila., 1865, p. 57. 

 Lepton rude (Dall manuscript) Whiteaves, Rept. Progr. Geol. Surv. Canada, 



1878-79 (1880), p. 198 B, fig. 2. 



B. 8. This differs from the type of Pseudopythina in having an obscurer 

 remnant of the cardinal hook in the shape of a small subumbonal con- 

 ical tooth, and less obvious radial striation, but is otherwise very simi- 

 lar. In both there is a well-marked calcareous coating to the ventral 

 surface of the resilium. The arcuate form is undoubtedly correlated 

 with its peculiar situs. (See Plate LXXXVII, fig. 4.) 



' In all these forms, whether the shorter end be anterior or posterior, its adductor 

 8c;ir will be more rounded and often larger than the scar at the longer end of the 

 shell, a result brought about in all probability by the dynamics of the situation. 



