PARTULA OTAHEITANA. 237 
All of the material is sinistral; apex is absent, so that only two color-types 
occur in each valley. Of these, cestata in Vaihiria is 10 times as abundant as the 
other (91.4 per cent of all), while in Vairaharaha it forms only 21.0 per cent of the 
whole association. The Vaihiria shells of this class (plate 31, figs. 25 to 28) grade 
from very dark examples, with considerable cross-suffusion of the bands (fig. 28), to 
almost clear yellow shells with only the faintest indication of the encircling girdle 
(fig. 25). 
The other color-class (plate 31, figs. 21 to 24) agrees in part with phza of earlier 
valleys, in so far as dark-brown shells with stained lips occur (fig. 22). 
Less intense 
solid browns are shown by the majority of the shells (fig. 21), but still others are 
present which are new in the details of their coloration (figs. 23, 24). 
TaBLeE 183.—Partula otaheitana sinistrorsa. 
Vaithiria and Vatraharaha Valleys. 
Mean VALUE. 
They display 
Shell. Aperture. Length aper- 
Serine: Neo. ture + length 
shell, propor- 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm, mm. Dace. p. ct. 
Vaihiria, cestata....| 277) 18.2687=.0317) 10.2329=+.0157] 55.9621 .0902) 9.2394 .0162| 7.0834 .0123} 76.5541 .1001| 50.5000+.0709 
phea..... 26) 18.3269 .0907) 10.2154 .0632) 55.7692+ .2685)| 9.2462 .0585| 7.1384+.0488) 76.8461 .3740) 50.4231+.1868 
Vaihiria, all........ 303} 18.2738 .0300) 10.2314+.0154) 55.9455 + .0813) 9.2399+ .0157| 7.0881+.0120| 76.5792 .0970| 50.4934 .0668 
51.2884+ .1494 
51.0282 + .0822 
Vairaharaha, cestata) 52 18.0443 .0779| 10.1385+.0378 56.1154=.1900) 9.2462 .0418) 7.0962-.0316| 76.3846+.1998 
phea..| 195} 18.1085+.0356) 10.1154+.0197 55.8282 .1020) 9.2559+.0214| 7.0385+.0154) 75.8743 +.1262 
Vairaharaha, all....| 247) 18.0949+.0325) 10.1202+.0174 55.8887 .0900; 9.2539-.0191| 7.0506 .0139| 75.9818 +.1085 
51.0830 .0741 
STANDARD DEVIATION. 
Vaihiria, cestata....| 277} 0.7821+.0224) 0.3886+.0110| 2.2262+.0638| 0.4009 .0114) 0.3047+.0087| 2.4702.0708| 1.7497+.0501 
phea..... 26 .6857 + .0641 4777+ .0447| 2.0297 .1898) .4422+.0414) .3680+.0345| 2.8277+.2644| 1.4121=.1321 
Vaihiria, all........| 303 -7745 = .0212 -3970+.0109} 2.0975+.0575| .4044+.0111) .3110+.0085) 2.5041+.0686) 1.7243+.0472 
Vairaharaha, cestata) 52 -8331+.0551 4039+ .0267| 2.0309+.1343) .4474+.0295|} .3385+.0223) 2.1362+.1413) 1.5977+.1056 
phea..| 195 -7382+ .0252 4075+ .0139) 2.1110+.0721) .4441+.0151] .3182+.0109) 2.6132+.0892| 1.7016+.0581 
Vairaharaha, all... .| 247 -7585 + .0230 4069+ 0123} 2.0977+.0636| .4448+.0135| .3234+.0098) 2.5289+.0767) 1.7262=.0524 
transverse strigations of medium brown upon a yellowish-brown background; these 
strigations are not as ill-defined as in the color-form noted earlier, which corre- 
sponds with the confluens of Pilsbry, nor is the ground-color so dark. For purposes 
of description, this subordinate color-form of the phza class will be called striata. 
Apparently, then, the unbanded class equivalent to phea of the neighboring eastern 
valleys has become more complex, although its variation is still continuous and has 
not led to its differentiation into distinct subgroups. In Vairaharaha very few of 
the strigated shells occur, and therefore the group corresponds more nearly with 
phea of Maara. 
In statistical respects (table 183) the two classes of each valley agree closely 
with one another. The two colonies differ in several characters, and in some 
instances the divergence is significant. One point of general agreement is found in 
the absolute lack of a columellar tooth, even as a trace; this is very important, for 
