THE NAUTILUS. 



VOL. XVII. AUGUST, 19O3. No. 4. 



TWO NEW MOLLUSKS FROM THE WEST COAST OF AMERICA. 



BY WILLIAM MICA LEY DALL. 



The National Museum lias received through the kindness of Mr. 

 J. S. Arnheim, of San Francisco, several interesting shells collected 

 by Capt. William Noyes, of San Francisco, of which two appear to 

 be undescribed. 



Sigarelus noyesli n. sp. 



Shell depressed, mottled purplish brown above, pale or nearly 

 while below, pale purplish with two obscure revolving brown bands 

 internally, nucleus minute, two-whorled, translucent, subsequent 

 whorls two, rapidly enlarging; surface with obvious incremental 

 lines, and faint, very fine, partially obsolete, spiral striation ; covered 

 with a yellowish silky periostracum j" suture distinct but not im- 

 pressed ; axis rather widely pervious, body with a slight, transparent 

 coat of callus ; pillar lip hardly thickened or reflected, general form 

 gibbous; alt. 10, major diam. 36, minor diam. 26 mm. 



Gorgona Islands, Colombia, in the Gulf of Panama. 



This species is a West American analogue of S. maculatus Say, of 

 the east coast, which is more solid, more convex, with much more 

 conspicuous spiral sculpture, and has the coil of the whorls impervi- 

 ous or nearly so. 



Tonlcia arnheimi n. sp. 



Shell small, back rather rounded, girdle narrow, naked, yellow 

 brown ; color pale pink with pale brown clotting, two white lines en- 



