224 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
produced apex and its own type, but no cestata. With a larger series of data it is prob- 
able that the third color-type would be found to produce banded young as well. In 
all cases, the embryonic snails are sinistral. 
In brief, then, the Vaiaaia association of sinistrorsa comprises three constituent 
color-types (apex, cestata, and phea), which are genetically interrelated, always sinis- 
tral, and toothless. 
Tasie 163.—Partula otaheitana sinistrorsa. Vaiaaia Valley. 
e Fercunpiry. Herepity. 
2 No. of | Per cent} No. of | No. of | Total Average | Average || Young,| Young, | Young, 
SETICS: ISOC: gravid.| gravid. | eggs. | young. | contents. |for gravid.) for all. || apex. | cestata.| phea. moult 
EVID no0000 56 45 80.3 70 31 101 2.24 1.80 9 22 We 31 
cestatamemie 78 62 79.5 80 51 131 2} stal 1.68 on 51 as 51 
phaser 5 4 80.0 3 (9) 9 2.25 1.80 3 ae 3 6 
JN Siero hoo 139 111 79.8 153 88 241 DMG 1.73 12 73 3 88 
AIAVARO VALLEY. 
In this region, phea 1s lacking in a series of 170 adult sinistrorsa; apex is less 
abundant in relation to cestata than it was in Vaiaaia. The shells illustrated in 
plate 30, figures 19 to 23, are unusual either in absolute dimensions or in propor- 
tionate measures. All are toothless. 
TasLe 164.—Partula otaheitana sinistrorsa. Aiavaro Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
ture + length 
Series. | No. 
shell, propor- 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm. mm. p. ct. Dp. ct. 
apex ....| 36] 20.0417+.1009} 11.0334+ .0446) 55.0078+.2703) 10.0445 .0577) 7.6723 .0486| 76.3055 +.3166) 50.0078 + .2312 
cestata ..| 132] 20.1467+.0549} 11.0864+ .0256) 55.0682 .1214) 10.0591 .0292)| 7.6637=+.0220| 75.5236+.1471| 50.3788+ .0934 
LW ho 00.00 168) 20.1250+.0483| 11.0750+ .0224| 55.0595+.1090) 10.1202+.0261) 7.6655+.0202) 75.6905 +.1351} 50.3036 .0889 
STANDARD DEVIATION. 
apex.....| 36) 0.8976+.0713) 0.3972+.0315) 2.4050+.1911) 0.5134+.0408 
cestata...| 132 -9345 = .0388 -4363+.0181| 2.0677+.0858 4977 + .0206 
0.4324 + .0343 
-3748 + .0155 
2.8168+ .2239) 2.0567+.1635 
2.5059 .1041) 1.5908+ .0660 
1 
IN 5.0106 168 -9278= .0341 -4316+.0158) 2.0950+.0771 -5013 + .0184 
3878 = O13 2.5956 .0955} 1.7087+.0628 
The colonial statistics (table 164) afford a basis of comparison with the Vaiaaia 
and other local groups. “They show, furthermore, that apex and cestata differ, and 
the differences are opposite in sign to those observed in the comparson of the same 
classes in Vaiaaia; the differences in question, however, are not in excess of their 
probable errors, saving only in the proportions of the aperture. The fundamental 
question is whether the genetic connection of apex and cestata in each valley is 
closer than that between apex groups of two neighboring valleys, or between cestata 
associations from two places; here and hereafter the former is the closer similarity, 
so far as statistical characters are concerned. 
