PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 345 



columella and the anterior end of the outer lip approximated, united by 

 a thin glaze of callus; interior polished, brown; base of the aperture 

 rounded, columella arcuate; umbilicus small, narrow, marked by raised 

 wrinkles of epidermis, which sometimes give it a carinated aspect from 

 their abrupt cessation at the umbilical margin ; base of the shell smoothly 

 rounded ; earlier whorls darker colored than the last. Alt. of shell, 10.0 ; 

 of aperture, 7.0; max. lat. of shell, 13.8; of aperture, T.On'-". 



Habitat : Pribilofl" and Aleutian Islands, Dall. Commander (Bering) 

 Islands, Stejneger. 



This group differs from the depressed "Lacunae like L. neritoidea in its 

 thin sharp columella, devoid of the excavated groove which gives the 

 genus its name, and in the reflexed margins of the aperture. It was 

 obtained by me in 1873-'74 in the western Aleutians and on St. Paul 

 Island of the Pribiloff Group. The types from which the above de- 

 scription was drawn are from the latter locality. It was compared 

 with forms in the cabinets of the British Museum, Copenhagen, Stock- 

 holm, Christiania, Bergen, Berlin, and the private collection of Prof. 

 G. O. Sars, and nothing found resembling it. 



There were two quite young specimens of this species in Dr. Stej- 

 neger's collection evidently identical with the above. Collector's num- 

 ber, 2779. Mus. Cat. 40928. 



Natica russa Gouu). 

 Bering Island. Collector^ number, 1901. Mus. Cat. 40929. 



Margarita helicina Fabricius. 



One young specimen from Bering Island. Collector's number, 2779. 

 Mus. Cat. 40930. 



Trichotropis insignis Middendorff. 



Eather common at Bering Island. Collectors' number, 2463. Mus. 

 Cat. 40931. 



Cerithiopsis stejnegeri, n. s. (pi. II, fig. 4). 



Shell small, thin, purplish, with white nucleus and columella, with 

 seven whorls ; nucleus smooth, partly immersed, about one turn in ex- 

 tent, followed by six strongly sculptured, rather rounded whorls ; sculpt- 

 ure consisting of four rather deep channels, between which are three 

 strong squarish revolving ridges about as wide as the channels ; the 

 channel next the suture nearly obsolete ; the most anterior channel bor- 

 dered anteriorly by an angular ridge, forming the periphery of the base 

 above whose general surface it does not rise and against which the sut- 

 ure runs in the penultimate whorl ; the three revolving ridges are nearly 

 equal in size; they increase, if at all, in succession forward, and are 

 crossed by less regular transverse riblets of about equal width ; these 

 squarish facets on the ribs, which, in the earlier whorls or in rubbed 

 specimens, become rounded nodules ; the pits of the reticulations are 

 quite deep, and in rubbed specimens look like rounded punctures on the 

 early whorls. The transverse riblets are less strong in the channels and 



