THE NAUTILUS. 



iVoi.. XL 



DECEMBER, 1897. 



No. 8. 



NEW WEST AMERICAN SHELLS. 



BY W. H. BALL. 



Sigaretus Oldroydii Ball, n. *i>. 



Shell large, thin, naticoid, with a short spire and 3-4 inflated 

 whorls ; color pale brown, livid on the spire, fading to waxen on 

 the base ; surface sculptured with extremely fine wavy spiral strise ; 

 aperture ample, oblique, the outer lip thin, a little patulous, the 

 body covered with a thin callus, the pillar lip obliquely cut away, 

 wide near the junction with the body, the basal part of the margin 

 receding ; umbilicus large, pervious, its walls covered with a thin, 

 silky, brown wrinkled epidermis. Alt. 35, diam. 37 mm. 



A single specimen in deep water off Catalina Id., Gala., collected 

 by Mr. and Mrs. T. S. Oldroyd. 



This species is easily distinguished from any other recorded, by 

 its very thin shell, naticoid form and wide pervious umbilicus. 

 Pecten Palmeri Dall, n. sp. 



Shell thin, orbicular, compressed, equilateral, white to yellowish- 

 brown, with concentric or zig-zag narrow bauds or flecks of dark 

 rose color; 15 strong ribs rounded in the young, mesially keeled 

 'and longitudinally threaded in the adult, separated by narrower 

 channelled interspaces, each with a mesial thread ; all crossed by 

 lamellose, concentric, rather sparsely distributed elevated lines; sub- 

 margins and ears closely radially threaded with imbricated threads. 

 Both valves similarly sculptured ; alt. 47.5, lat. 53, diameter about 

 20 mm. 



