306 MOLLUSKS OP BERING SEA. 



Cingula robusta Dall. 



C. robusta (Dall MS.) Krause, ?. c, p. 270, t. xvii, fig. 1, a-h. 



This species has been well figured by Dr. Krause, who kindly adopted 

 the manuscript name under which I have sent out numerous specimens 

 during the twelve years it has been in my collection. Since his paper 

 was received I have been informed that the name robusta has been used 

 for another species of the same group. Kot having the means of veri- 

 fying this statement at the present moment, I propose to figure the two 

 extreme forms under which I have found this species at Kyska Harbor, 

 Aleutian Islands, and to apply varietal names to them ; the name re- 

 ferring to the stout variety to be adopted for the species in case it be 

 found necessary to drop the name of robusta. 



Cingula robusta var. martyni Dall (PI. Ill, fig. 9). 



This is the most common and apparently the normal form, collected 

 by me in the Aleutians and by Krause at Plover Bay, Eastern Siberia. 

 The specimen figured is 5.0™™ long. It is dedicated to the naturalist 

 Martyn, whose beautiful figures in the Universal Couchologist gave the 

 first adequate representation of some of our best known species from 

 Northwest America. 



Cingula robusta var. scipio Dall (PI. IV, fig. 10). 



This form is much rarer than the preceding, about 1 per cent, of 

 those collected being of this sort, but with a certain number of interme- 

 diate grades. Should the differences be sexual, as in some Hydrobiinw, 

 these slender ones would be males. There seems to be no other dif- 

 ference than that of form, faint revolving lines being occasionally pres- 

 ent in both; both are of the same reddish grape-color with whitish 

 bloom, and whitish border to the aperture. The figures are on the same 

 scale and show the proper relative proportions. 



Onoba saxatilis Moller (PI. Ill, fig. 8). 



Rissoa {PaUidinella) saxatilis Moller, Ind., p. 9, 1842. (f. Friele.) 



liissoa arctica Lovea (f. G. O. Sars, Friele). 



? Cingula leptalea Verrill, Tr. Conn. Acad. VI, p. 182, pi. 32, fig. 10, 1884. 



The specimens identified by both Sars and Friele with saxatilis of 

 Moller have from four to five whorls and vary between 2.25 to 2.75™™ in 

 total length. The Alaskan specimen above figured is full-sized, being 

 2.75™™ in length. The fine spiral sculpture is only feebly developed, and 

 varies with different specimens of saxatilis. The outline, «&c., agreeing 

 so closely with Professor Verrill's figure, and the other characters being 

 very much the same, I cannot help suspecting that his leptalea may prove 

 to be only a finely developed saxatilis. The identification of the Nor- 

 wegian form with G. aculeus Gould and both with B. saxatilis or arctica^ 

 as made by Prof. G. O. Sars, seems more than doubtful and requires con- 

 firmation, though both may be found on the Norwegian coast. The New- 

 England aculeiis is certainly not the same as the arctic specimens from 



