'/ THE NAUTILUS. 



and white margin. Lower California and the Gulf. Fossil at San 

 Diego and Cerros Island. 



O. CUMINGIANA Dunker, Abbild. II, 1847. (0. amaraCpr., 1857; 

 O. angelica Rochebrune, 1895. A variety, 0. mexicana Sowerby, 

 1871). 



The typical form has olive greenish interior, the margin with 

 many small plic.ntions, the exterior white. The variety is deeply 

 cup-shaped with blackish interior margin. The species ranges from 

 Lower California to Panama. 



O. PALMUI.A Carpenter, 1857 (0. lucasiann Rochebrune, 1895). 

 Puget Sound to La Paz, Mexico. 



Margin bounded inwardly by a line of minute pustules, interior 

 dark or greenish. This might well be an extreme mutation of the 

 preceding species but needs connecting links and has a more north- 

 ern distribution. 



O. SERRA Dall, n. sp.? Lower California to Panama. 



Like the West-Indian species which grows on gorgonians, narrow, 

 plicate, with flatfish upper valve, deep lower valve, greenish outside? 

 inside white with black margin ; shell two to three inches long, about 

 an inch wide. If mexicana occupied a similar situs the result would 

 be somewhat similar. 



O. COLUMBIENSIS Hanley, 1845. (O. ochracea and tulipa of 

 Sowerby, 1871, not 0. tulipa Lamarck ; 0. turturina of Roche- 

 brune, 1895). On mangroves. Lower California to Peru. 

 Large, thin, purplish. 



O. LURIDA Carpenter, 1864. Sitka to Cape St. Lucas. 



0. rufoides is (he thin, long variety grown in a current. 0. 

 expansa the form adhering to a flat surface ; sometimes reaching the 

 shape called by Carpenter laticaudatus. 



O. ELONGATA Solander, 178fi. (0. virginica Gmelin, 1792; 0. 



rostrata and floridensis Sowerby, 1871 ; 0. virginiana, canadensis 



and borealis Lamarck, 1819.) 



Transplanted from the middle Atlantic coast it has failed to re- 

 produce its kind, as the water is too cold for the spat to live in. 



