42 DIVERGENCE UNDER THE SAME ENVIRONMENT. 
The relative numbers in which these different variations occur are 
roughly indicated in the following table, in which the numbers not 
inclosed in parentheses correspond with the figures in Plate III, while 
the number in parentheses below each one of these indicates approxi- 
mately the relative frequency in which it was found. 
I 2 3 4 5 6 7 8 9 10 II 12 13 
(200) (150) (100) (60) (30) (200) (200) (200) (200) (100) (200) (200) (200) 
I 15 16 ey 18 19 20 21 22 23 24 25 
(100) (60) (1) (200) (200) (200) (60) (30) (300) (45) (15) (15) 
The metropolis of Bulimella rosea is Wahiawa, where the most 
abundant type of coloring is seen in figure 22, which is snowy white 
with a pink lip. In Helemano district, the shells of this species are 
somewhat smaller, with the lip more frequently white, and the body 
of the shell not as snowy white as is usually the case in the metropolis. 
Figure 21 isa comparatively rare variety of B. rosea, white throughout 
and intergrading with B. ovata through a nearly white variety of the 
sinistral form of that species, occurring in Kahana in the proportion of 
perhaps one to a thousand of the normal specimens of the species. 
Again, in figure 16, we have a very rare form connecting Bulimella 
obliqua with Bulimella ovata. 
OAHU THE METROPOLIS OF THE ACHATINELLIDA. 
The island of Oahu may be regarded as the metropolis of the Acha- 
tinellide, for on this island we find 8 of the ro genera, while on Maui 
and Molokai together we find 7 genera, and on Kauai 3 genera. Suf- 
ficient attention has not been given to the land snails of Hawaii to 
enable us to give a full report; but I am told that there is an unusual 
development of Succinea on that island, while the Achatinellidz are 
but very meagerly represented. One explanation of the small devel- 
opment on the island of Hawaii of the family of snails which is so 
fully developed on the island of Oahu is found in volcanic eruptions, 
which on the island of Hawaii have from time to time destroyed the 
forests till recent years; while on the island of Oahu it is probably 
hundreds of thousands of years since such complete destruction of the 
necessary conditions of existence for these creatures has occurred. 
