NO. I ACHATINELLA APEXFULVA DIXON — WELCH 203 



tion, then, can be drawn in the majority of ridge complexes between 

 increase of size with increase of moisture and lower temperature. 

 This is the reverse of what was fo\md for A. mustelina, which species 

 shows a correlation between decrease of size and increase of moisture. 

 Therefore, these two different species react very differently to similar 

 environmental conditions, the reaction probably depending not only 

 on the genetic make-up of the individual but also on the influence of 

 the environment on the hereditary factors. 



4. SHAPE 



If the usual form of the shell from each area is considered and 

 the ratio of the length to the greater diameter is obtained, the usual 

 form of the shell is found to vary at random. Only in ridge complex 

 15 is any vertical variation shown; here the lower areas contain 

 narrower shells than the highland areas. This general condition is 

 similar to that found in the case of A. mustelina (Welch, 1938). 

 In most areas in the Waianae Mountains A. mustelina showed no 

 vertical variation. Only in the northern section of the mountains is 

 the shape of the shell found to change from elongate lowland to more 

 squat highland forms. 



C. Variation within a Locality or Area 



I. COLOR PATTERN OF EMBRYONIC AND POSTEMBRYONIC WHORLS 



Each subspecies in a given locality has a range of color patterns 

 from light to dark. The dark color patterns of shells from some areas 

 in zone III in regions I and II are often very different from the usual 

 white color form of the shell. In area 8 (pi. 4, fig. 15&), area 12 

 (pi. 4, fig. 20b), area 11 (pi. 5, fig. 2b), area 10 (pi. 5, fig. la), and 

 area 46 (pi. 7, fig. 14a) dark reddish-brown forms occur which would 

 never have been expected in an area of white shells. One of the 

 most striking examples of this occurrence of two widely dift'ering 

 color patterns from the same locality is to be seen in the region of 

 the North Kaukonahua area 103 of A. a. roseipicta var. i. The domi- 

 nant color pattern (pi. 3, fig. 8) is a pinkish one banded with white, and 

 the other color patterns are white ones banded with pink. With these 

 patterns, a few rare dark gray color forms occur (pi. 12, fig. 6) which 

 are strikingly dift"erent. The same thing occurs in area 105. In area 

 100? the strikingly banded patterns of A. a. aloha var. i may be an 

 example of the same thing, but in this locality the patterns are not 

 only different but show a series of variants which may indicate a 

 separate area containing special color patterns. 



