262 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
Fecundity (table 212) is low, and hence there are scanty data for the determina- 
tion of the facts of heredity (table 213). The latter are very interesting, however, 
because in summary the numbers of sinistral and dextral young are almost exactly 
the same as those for gravid parents; the appearance of bands is apparently delayed 
in development, for plain young preponderate in all arrays. 
TasiLe 213.—Partula otaheitana sinistralis. Tereehia Valley. 
Fury Data oF Herepity. SUMMARY. 
Young, sin. Young, dex. 
Total. vous Noane Total. 
Unbanded.} Banded.| Unbanded.| Banded. i ; 
Adults: Adults: 
Sin., unbanded....... 1 ar 1 a5 2 Singer 8 4 12 
band edaeerieererer 7 on 2 1 10 IDYS eaaoei 5 24 29 
exe band cd aeeeweraesrer 4 1 18 6 29 
—_ | |——_____ |__| Total....... 13 28 41 
Mo tale erence ae eee 12 1 21 7 41 
Tramao VALLEY. 
Tiamao is the third and last area which is inhabited by any considerable 
numbers of dextral sznistralis in addition to the more characteristic reversed kind. 
The valley is smaller than Tereehia, but it is thickly populated by Partule. 
Of 177 adults (54 per cent) that are sinistral, 8 only are devoid of bands, and 
display the phea confluens coloration, although in one or two there is some degree of 
approach to the striata subtype. The contrasted cestata shells fall into the three 
subclasses established earlier, viz (a) faint bands on body-whorl (plate 32, figs. 44 
and 45), (2) distinctly banded throughout (plate 32, figs. 46 and 47), (c) suffused 
color on the last whorl (plate 32, figs. 48 and 49); the numbers are 29, 68, and 72, 
respectively (about 17 per cent, 40 per cent, and 42 per cent). 
Among the dextral and unbanded shells is one that is virtually an apex in ground- 
color, but it lacks the dark spire of typical apex in other snistralis colonies (Teohu) 
and in sinistrorsa (plate 32, fig. 50). The remaining plain shells belong to the pha 
group (plate 32, figs. 51 and 52), without definite segregation into striata and confluens. 
Banded dextral shells of all three subordinate kinds occur (plate 32, figs. 53 to 57) 
as follows: (a) 19, (0) 57, and (c) 63 (13, 41, and 45 per cent, respectively). 
The statistical analysis of this colony is carried out in further detail than 
heretofore, because the dextral series is more like the sinistral part of the population 
in make-up. The figures are given in table 214. The major points are: (1) the 
sinistral and dextral groups are virtually the same in all characters; (2) the unbanded 
group differs from cestata in the same way in both coils as far as the measures of the 
shell as a whole are concerned, but in different ways in other characters, without 
any regularity; (3) the three subordinate cestata groups differ inter se more often in 
absolute dimensions than in the proportionate measures. In brief, the interrela- 
tionships of all recognizable groups are so close as to render the colony as a whole 
a somewhat compact one in genetic constitution. 
