136 THE NAUTILUS. 



cords with narrower interspaces ; umbilical area imperforate, smooth, 

 slightly excavated, white ; pillar arcuate ; smooth ; aperture very 

 oblique simple, pearly white within ; operculum ? Height of shell 

 32.5 ; of last whorl 20.5 ; of aperture (vertical) 1 1.5 ; max. diameter 

 36.5 mm. 



U. S. Fish Commission station 2983, off Cerros Island, Lower 

 California, in 58 fathoms, sand. U. S. Nat. Mus. 111241. 



Of three dead specimens dredged, one had the periphery com- 

 pressed and roundly keeled, and on the spire were some feeble indi- 

 cations of axial ribbing. 



NEW MARINE SHELLS FROM THE NORTHWEST COAST OF AMERICA. 



BY PAUL BARTSCH,^ 



Assistant Curator, U. S. Kational Museum. 



In a collection of mollusks submitted to the U. S. National 

 Museum for critical examination, by Dr. Fred. Baker of San Diego, 

 California, collected by him on the Northwest Coast, are several 

 new forms which are here described. 



The types of these species have been kindly donated to the 

 National Museum by Dr. Baker. 



Leptogyra alaskana new species. PI. XI, figs. 4, 5, 6. 



Shell minute, depressed helicoid. Nuclear whorls one and one- 

 half, light yellow horn color, marked by faint incremental lines. A 

 single post-nuclear turn follows which is bluish white, rather bread 

 and gently, almost evenly curved from the well-impressed suture to 

 the periphery. This whorl is marked by about twelve, fine, incised 

 spiral lines between the suture and the periphery which are stronger 

 toward the periphery than at the suture. Periphery of the last 

 whorl rounded. Base broadly and deeply umbilicated, strongly 

 arched, with a slender cord at the junction of the basal and parietal 

 wall, surface of the base marked by incised lines which are equal in 

 strength and number to those occuring upon the upper surface. 

 Wall of the umbilicus almost flat, marked by faint spiral lines. 



^Published by permission of the Secretary of the Smithsonian Institution. 



