THE NAUTILUS. 29 



callus; columellar lip reflexed over one-third of the umbilicus; 

 aperture oblique showing the bands within. 



Four specimens give the following measurements: 



1 type No. 35601 



2 



3 



4 



Specimens of this new species were included in a large col- 

 lection of Philippine shells given to the Museum of Comparative 

 Zoology by W. Cameron Forbes, former governor of the Philip- 

 pine Islands. They were collected by Mr. C. W. Weber at 

 Bacuit, northern Palawan. I have named this shell for Gov- 

 ernor Forbes as a slight acknowledgment of the great interest 

 that he has taken, and the work that he has accomplished, in 

 adding to our knowledge of the fauna of the Philippine Islands. 



The specimen selected as the type, and described, is the most 

 typical of the species. The specimen designated as number 

 two in the table of measurements, is exactly similar to number 

 one in color, and in the arrangements of the bands, differing 

 only in being more depressed. Number three is very similar to 

 number two in size and shape, but differs from numbers one 

 and two in color, the lower band in this form having spread 

 over the entire base, the upper band extending to the suture, 

 leaving only at the periphery a narrow band of the typical 

 naples yellow. Number four is similar to the type in size and 

 form, and to number three in color. The variation is therefore 

 expressed along two independent lines; first, a tendency for the 

 shell to become more or less depressed; and secondly, for the 

 bands to become broader and darker. Intermediates between 

 all forms are in the series before me. The tendency in each in- 

 dividual specimen for the color to become darker as the shell 

 increases in size, is constant in both the light and the dark 

 forms. 



The differences between this species and the description of 

 what appears to be the most closely related species, Camaena 



