ACHATINELLA CASTA. 237 



lula. According to Mr. Thwing, A. casta ranges from Halawa 

 to Waipio ; but this extension eastward is very doubtful. 



Numerous supposed species have been based upon forms of 

 casta, but after seeing the great series brought together by 

 Messrs. Spalding, Thurston, Cooke and Thaanum I agree with 

 Dr. Cooke that no sufficient ground exists for admitting them 

 as races. They are, we believe, selected forms out of colonies 

 which in other specimens "run into" other forms of casta. 

 The explanation of Mr. Gulick's over-division of casta (which 

 lured Mr. Smith into describing so many forms), is found in 

 the fact that there is a marvellous opulence of color-mutation. 

 Very often some special pattern predominates in, or at the 

 height of its development is special to, a certain colony. 

 Working with small series from scattered colonies, the differ- 

 ences are unduly obvious. A. casta deserves monographic 

 treatment, with several plates, but this work cannot properly 

 be done except in Honolulu. 



Waimano. PL 49, figs. 2, 3, 4, 5, coll. by C. M. Cooke, on 

 northern ridge and lateral ridges of the valley. The most 

 abundant pattern is some shade of yellow, more or less passing 

 into brown, with darker lines or bands. There are also a few 

 copiously streaked shells, with two dark bands; two of this 

 pattern being dextral. Others have dark zones which nearly 

 cover the surface. Two shells are deep chestnut with lighter 

 streaks. Other Waimano patterns are shown in pi. 41, figs, 

 figs. 13 to 13c, Cooke collection. 



One lot contains some specimens which approach A. c. mar- 

 gar eta in coloration, having two tawny bands on a whitish 

 or yellow ground, and a pink columella (pi. 49, fig. 5). The 

 shape and texture are the same as in other patterns of casta 

 found with them. Mr. Spalding found the same pattern in 

 the eastern ravines of Waiawa. 



Some Waimano shells, such as pi. 49, fig. 4, approach 

 A. pupukanioe, but on account of the form of the columella 

 in old shells, I believe that the latter is an entirely distinct 

 species. 



PL 41, figs. 14-14& are from the A. cookei ridge, Thaanum. 



Waiawa. A. casta is found in both division ridges of 



