1886.] PEOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 307 



Alaska or Greenland, which are not over one-half the size of aculeus, 

 which is about 4,00 to 4.25""" long. It is much nearer to B. proxima 

 than to R. striata; indeed, it does not seem from my specimens especially 

 close to 0. striata as has been claimed. 



The species is extremely rare in the Aleutian Islands, where a few 

 specimens were obtained at Nazan Bay, Atka Island, from the ripple- 

 marks on the sandy beaches. 



Onoba cerinella Dall (PI. IV, fig. 12). 



This species is quite close in form to 0. proxima Alder, as figured by 

 Jeffreys and G. O. Sars. It differs from that species in the total ab- 

 sence of spiral striation, in having a less truncated apex and one less 

 whorl in the same length, 3.0™">. There is a slight chink behind the 

 reflexed inner lip, the surface is smooth but not polished, the sutures 

 distinct but not deep. A few specimens collected at Atka Island with 

 the last specimens were regarded as distinct from 0. proxima and other 

 related European forms by those who examined them, in 1874. 



Onoba aleutica Dall (PI. Ill, fig. 11). 



Shell resembling G. minuta Totten, but more slender and smaller; less 

 slender and drawn out than 0. aculeus Gould, and having no spiral lines 

 like the latter; color light warm brown; surface smooth, with faint 

 growth lines, no spiral sculpture; loosely coiled; the aperture simple, 

 peritreme continuous, slightly reflexed, its edge black, inside whitish, 

 hardly touching the body whorl and with a chink, or umbilical space 

 extending far behind it, but not into the axis. Shell often eroded in 

 spots, thin, with distinct sutures and neatly rounded whorls. Extreme 

 length of specimen figured 3,5™™, Very rare in ulvse at Uualashka, 

 Aleutian Islands, 1874. 



Alvanea castanea Moller, var. alaskana Dall (PI. IV, fig. 9). 



1 Rissoa castanea Moller, Index, p. 9, 1842. Sars, Moll. Reg. arct. Norv., p. 174, 

 pi. 10, figs. la-i. 



A shell found at Nunivak Island in 1874, and figured above, was re- 

 ferred to M oiler's species by both Friele and Professor Sars. It differs 

 from the typical form in having the same number of whorls in five- 

 eighths the length of the former, in the greater prominence of the 

 wrinkles extending forward from the sutures, and in being much thinner 

 than the castanea generally is, I am informed that the castanea is a very 

 variable form, and notwithstanding the typical castanea has not yet 

 been found in Alaska, I prefer until the receipt of more information to 

 refer this shell to it as a variety. The specimen figured is 2,5™™, in 

 length, and of a pink color, fading into white toward the apex, with 

 traces of a pale thin smooth yellowish epidermis. 



Alvania castanella Dall. (PL III, fig. 5.) 



The verdict on this species, after comparison with all those of North 

 Europe and Greenland, was that it was nearest to but distinct from 



