66 THE NAUTILUS. 



nut-brown within, at least in large part, not quite circular, being a 

 little longer than wide, and with the inner margin less arcuate than 

 the outer. Peristome moderately broad, witli a low, brown, raised 

 inner rim, and whitish or white expansion, which is dilated into a 

 slightly recurved or concave lobe above, adnate to the preceding 

 whorl ; it is also a little dilated at the columellar margin. The um- 

 bilicus is smooth within, but rarely shows faint traces of a few spiral 

 cords. 



Length 17, diam. 13 mm. 



Length 15, diam. 11 mm. 



The operculum is white externally, slightly concave, rather coarsely 

 -wrinkled tangentially, and with about 2^ whorls after the blackish 

 .nucleus, which is situated at about the lower third, and much nearer 

 the columellar than the outer margin. The edge is very deeply 

 grooved, the sides of the groove smooth or nearly so. 



Braco, Trelawny, in northwestern Jamaica, the types collected by 

 Mr. George Nutt, and sent by Mr. P. W. Jarvis. 



This species differs from G. chevalieri in the sculpture of fine vertical 

 stria?, the obsolescence of spiral cords around the umbilicus and in col- 

 oration. C. albus, which has similar sculpture and operculum, differs 

 in the narrow lip, not dilated above. The latter species is the most 

 nearly related form known to me. 



Sometimes the wide median color zone is split by a lighter per- 

 ipheral tract ; or it may be reduced to a narrower belt below the 

 periphery. 



NOTES ON THE MOLLUSK FAUNA OF SAN NICHOLAS ISLAND. 



BY HERBERT N. LOWE. 



San Nicholas, the most bleak and barren bit of land in the whole 

 group of the Santa Barbara Islands, lies apart from its more favored 

 sister islands, sixty-five miles from the mainland. It is a small 

 island, barely nine miles long, by four or five wide, without a vestige 

 of a tree of any kind, and very little of the cactus, which grows in 

 such quantities on the other islands. About half its area is a great 

 desert of shifting sands where lie the bleaching bones of an extinct 

 .race of Indians which inhabited the island many years ago. Many 



