298 MOLLUSKS OF BERING SEA. 



obtained in the same region by myself and b}' the Point Barrow expe- 

 dition, and whicli I regard as distinct from Admete viridula of authors. 

 My friend, Dr. Krause, in his paper on the moUusks of Bering Sea 

 (Arch. f. Naturg., 1885, p. 273), regards this figure as intended to repre- 

 sent A. viridula var. Icevior Leche. In the light of this criticism, and 

 with the aid of specimens of that variety submitted by Dr. Krause, I 

 have reviewed my material, consisting of some hundreds of specimens 

 of all varieties of the Admete from all parts of the coasts of Ahiska and 

 Bering Sea, as well as various parts of the Arctic Ocean. I conclude 

 that, whatever Middendorfl's figure may be intended to represent, the 

 species I referred to it is distinct from Admete and perhaps a typical 

 Canccllaria. Its external appearance is certainly very similar to the 

 variety Icevior^ from which, however, it differs in the following particu- 

 lars: The shell is stout and heavy, not thin, as Admete invariably is; 

 the proportions and sculpture in a large series are extremely uniform^ 

 while the Admete is very variable; the columella has a distinct siphonal 

 fasciole, wanting in Admete; the interior of the aperture is periodically 

 thickened and furnished with eighteen or twenty strong liroe which do 

 not reach, but are separated by a smooth space from, the outer lip and 

 have no connection with the external grooved sculpture; the sculpture 

 is stronger and more uniform, the revolving ribs flatter than in Admete, 

 and there is an absence of the tendency in the latter to intercalary tiner 

 threads. Its claim to specific rank was not disputed by any of the ex- 

 perts to whom it was submitted. 



An examination of several hundred Admetes does not show a single 

 specimen with the raised lirse. The Cancellaria is a strictly Arctic 

 shell, and has not been found south of the northern end of Nunivak 

 Island by any one, while the Admete is common everywhere among the 

 Aleutian Islands, and in all its varieties, Icvvior included. 



Cancellaria middendorffiana is of a chalky or j^orcelanous white, with 

 a pale yellow epidermis. An average specimen has five whorls with a 

 length of shell of 17.5, of aperture of 10.0, and a greatest total breadth 

 of 10.5'"'". It has a general resemblance (such as an arctic shell may 

 have to a tropical one) to C. sinensis, as figured by Eeeve, except that 

 the spiral ridges on the columella, generally two or three, are obscure 

 and not sharp. 



In this connection it may be observed that tlie original type of 

 Tritonium viridulum, O. Fabr., as well as the Defroncia viridula of 

 Mdller, founded on the same specimen, is a Bela, like B. exarata, and 

 not an Admete at all. This has already been mentioned by Morch, and 

 was confirmed by an examination of the shell at Copenhagen. The 

 earliest identifiable name of the Admtte viridula of authors is Cancel- 

 laria huccinoides of Oouthouy (Feb., 1838); but there being already a 

 Cancellaria of that name, Dr. Jay in 1839 named it Admete couthouyi. 

 This specific name was adopted by Gould in 1811 and has several 

 years priority over Holler's Admete crispa (1812). In accordance with 



