84 



THE NAUTILUS. 



stretched the shore with the blue Pacific and endless lines of 

 snowy surf. 



We started for home at 6.30, arriving at 9:00 a. m., tired and 

 well pleased with our trip. 



Among the shells collected were: 



Cypraea mauritiana L. Nerita picea Recluz. 



Cypraea caput-serpentia L. Nerita polita L. 



Purpura harpa Conr. Littorina pintado. 



Purpura intermedia Kien. Littorina picta Phil. 



Ricinula horrida Lam. Littorina feejeennis. 



Ricinula morus Lam. Acanthochites viridis Pse. 



Ricinula ricinus L. Helcioniscus exaratus Nutt. 



Ricinula tuberculatus Blain. Strombus maculatus Nutt. 



Comes ceylonensis Hwass. v. Siphonaria amara Nutt. 

 pusillui. Siphonaria amara var. 



Conus hebraeus L. Columbella zebra. 



Conus lividus Hwass. 



Conus abbreviates Nutt. 



NOTE ON ALABA AND DIALA. 



BY W. H. BALL. 



In working over some of the minuter Hawaiian shells it be- 

 came necessary to make comparisons with Diala and Barlceia, 

 etc. 



Examination of the Pacific coast species referred to by Car- 

 penter revealed some unexpected peculiarities. 



The genus Alaba was named by A.rthur Adams in December, 

 1853, in the "Genera of Recent Mollusca," p. 241. It contained 

 two species, both West Indian, of which the first, Rissoa me- 

 lanura C. B. Adams, is now selected as the type. 



The genus Diala was proposed by Arthur Adams in 1861, with 

 five species of which the first, D. varia A. Adams, is now selec- 

 ted as type. This group closely related to Alaba, differs by the 

 absence of varices, and generally more compact and flatsided 

 shell. Diala was adopted by E. A. Smith in 1875, who figured 



