20 THE NAUTILUS. 



Strait a number of species of shells were procured, some of which 

 are widely distributed in the boreal seas while others are local. 

 Many of the specimens were exceptionally large, larger than others 

 of the same species collected elsewhere. In sorting the material, 

 which has been all these years in alcohol, a remarkable new species 

 of Admete was found, of which the description follows : 



Admete kegina n. sp. 



Shell large, solid, white, with a coffee-colored periostracum and 

 five or more whorls, the apex in every case being more or less 

 eroded ; spiral sculpture of fine, even-channeled grooves with flat- 

 tened or even slightly concave wider interspaces, covering the whole 

 shell except a space between the suture and the shoulder of the 

 whorls ; there are about two grooves and an interspace to a milli- 

 meter ; axial sculpture of a few feeble often more or less obsolete, 

 irregular, low plications, not quite reaching the middle of the whorl ; 

 suture very deep but not channeled ; whorls moderately rounded ; 

 base attenuated, with a narrow, deep umbilical perforation ; outer 

 lip simple, hardly thickened, throat white, smooth, body with a 

 smooth, white layer of callus ; pillar concavely arcuate, with six or 

 more feeble plaits, the anterior end of the pillar projecting over a 

 deep notch. 



Height of shell 36, last whorl 27, of aperture 20, max. diam. 

 22 mm. 



Type No. 221473, U. S. N. Mus.; dredged in Plover Bay in 25 

 fms., hard bottom, by W. H. Dall in 1874. 



THE CLASSIFICATION OF THE EUROPEAN NAIADES. 



BY DR. A. E. ORTMANN. 



( Concluded from page 7). 

 I have divided the family Unionidce into three subfamilies, only two 

 of which are found in Europe (compare : Nautilus, 23, Febr. 10, p. 

 114-120). 



Subfamily: Unionin^ Swainson (restr.) 



Supraanal opening rarely not separated from the anal, generally 

 well separated. Marsupium formed by all four gills, or only by the 

 outer ones, when charged only moderately swollen, and its edge not 



