678 rROCEEDINGS OF THE NATIONAL MUSEUM. vol.52. 



and equalh' spaced low, well-rounded spiral cords, which are a little 

 wider than the spaces that separate them. xVperture subcircular; 

 posterior angle obtuse; outer lip strongly curved, rendered somewhat 

 sinuous by the external sculpture ; inner lip strongly curved ; parietal 

 wall covered by a thick callus which renders the peritreme almost 

 complete. 



The type and three specimens of this species. Cat. No. 271407, 

 U.S.X.M., were collected by Dr. William H. Dall in,shallow water 

 at Kyska Harbor, Aleutian Islands, Alaska. The type has 3^ post- 

 nuclear whorls and measures — length, 2.5 mm. ; diameter, 1.2 mm. 



ALVANIA DINORA, new species. 



Plate 46, fig. 5. 



Shell small, elongate ovate, yellowish white. Nuclear whorls two, 

 strongly rounded, smooth. Postnuclear whorls strongly rounded, 

 almost appressed at the summit and moderately constricted at the 

 suture, marked by 7 very low, flattened spiral cords between the 

 sutures, which are separated by a shallow impressed line. The axial 

 sculpture consists of numerous very slender threads which are almost 

 vertical. Suture strongly constricted. Periphery of the last whorl 

 somewhat inflated, well rounded, base moderately long, slightly at- 

 tenuated anteriorly, marked by 6 low, ill-defined rounded spiral cords, 

 which, like those on the spire, are separated by mere impressed lines. 

 The axial ribs also continue over the base. Aperture broadly oval, 

 decidedly effuse at the junction of the basal and the outer lip; poste- 

 rior angle obtuse; outer lip thick within, thin at the edge, evenly 

 curved from the posterior angle to its junction with the inner lip; 

 inner lip decidedly curved, somewhat reflected and appressed to the 

 base; parietal wall covered by a thick callus, Avhich practically ren- 

 ders the peritreme complete. 



The type. Cat. No. 268730, U.S.N.M., and three additional speci- 

 mens of this species, were collected by Mr. Willis at Forrester Island, 

 Alaska. The type has a little more than 3 postnuclear whorls and 

 measures — length, 2 mm.; diameter, 1 mm. 



This is a very small species with very feeble sculpture. 



In addition to these new species of Alvania, we have seen the addi- 

 tional specimens listed under the species mentioned below since the 

 publication of my little monograph on The Recent and Fossil Mol- 

 lusks of the Genus Alvania from the AVest Coast of America.^ 



It may be well to mention here that recent studies in the classifi- 

 cation of the group will make it necessary to redistribute the mem- 

 bers which we have brought together under the genus Alvania among 

 several groups. I refrain from doing this at this time, because I 

 wish first to examine the type-species of all the supraspecific groups 

 before giving a final opinion. 



iProc. U. S. Xat. Mus., vol. 41, pp. 333-3G2, pis. 29-32. 



