390 



BULLETIN 10 0, UNITED STATES NATIONAL MUSEUM 



a zone of brown at the summit and frequently a narrow line of brown 

 showing above the suture. Both of these brown lines as a rule grad- 

 ually increase in width until they entirely blot out the light zone 

 between them. The base is usually unicolor, although sometimes 

 the umbilical area, which is dark, is bordered by a little paler zone 

 posteriorly. The interior of the aperture is bluish white, and the 

 outer lip is brown; the columellar area though white is occasionally 

 tinged with brown. When the periostracum is present this is usually 

 of a dull wood-brown color, sometimes faintly spirally lined. 



I have two shells before me that are pale orange and suggest in 

 their color scheme the orange form from Ilin Island, but in shape 

 they conform more with subatra. There is no definite locality men- 

 tioned. A series of 38 specimens yields the following measurements: 



