46 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 



Hab. North Greenland, north of Baal's River. 

 Collect. University of Copenhagen ; Prime. 



I took occasion, while in Copenhagen, to have a drawing made of this 

 species from one of Moller's original types. 



Closely allied to P. j^ulchellum, but the lines of growth are finer, al- 

 though the shell is larger. 



Clessiu, in his synonymy of this species,^ is at fault ; he ignores my 

 first four references, and makes it out that this species was first described 

 in 1868,- and not by Miiller as a Cyclas, but by Morch as a Pisidium, 

 which is not correct. 



1 Mart, and Chemn. Cycladea, 35, 1877. 

 fl Am. J. Conch. 1868. 



