134 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
The color analysis of the sinistral and dextral divisions of the colony shows that 
they differ from one another more than the corresponding divisions of the Fautaua 
colony (table 67; compare with table 60), but it is questionable whether a fuller series 
of shells would show the same discrepancies. Probably the 6 per cent of dextral 
Class I shells in 1906 and the zero for 1909 would increase to a figure much nearer 
to the 22 per cent of 1907; the percentages for the sinistral shells are far more 
uniform, although even they are less consistent, especially in the case of Class IV, 
than in the fuller series from Fautaua. A point of special interest is that Class III 
in both coils is close to 50 per cent, as it is in the first-described valley; there is a 
great decrease in this respect when the next valley of Pirai is reached. 
The significant statistical data relating to the standard dimensions of the two 
classes are given in table 68. On the whole, the dextral shells agree quite closely 
with the others, much more so than in Fautaua Valley. In length only are the 
former larger with statistical significance, where the difference exceeds thrice its 
error. In only two of the seven characters do the sinistral shells differ from the 
dextral group in the same way as in the Fautaua colony; these are, namely, the 
total length of the shell and length of aperture. In all of the other characters there 
is a reversed relation, or else the difference in the Hamuta colony is devoid of 
statistical significance. 
TaBLe 68.—Partula otaheitana amabilis, Hamuta Valley. Comparison of sinistral and dextral classes. 
Sinistral (289). Dextral (166). Differences. 
Character. SS SSS 
Standard Standard Standard 
MAGEE VELER: deviation. Nae VEE deviation. SHEED VENI. deviation. 
Shell, length, mm..... 18.3282 + .0332} 0.8359+.0235|] 18.5018+.0475| 0.9070 + .0336} —0.1736+.0579| +0.0711=+ .0406 
width, mm..... 10.7097+.0172| .4396+.0122| 10.7844 .0262} .5000+.0185| — .0747+.0313]— .0604+.0221 
proportions, 
DinCtirecerr 58.4100 + .0928] 2.3409 .0656| 58.1988 .1118] 2.1353+.0790| + .2112+.1453]/+4 .2056+.1027 
Aperture, length, mm..| 9.5617+.0190] .4833+.0134] 9.6506+.0284| .5433=.0201|— .0889=+.0341]— .0600+.0241 
width, mm..| 7.4979+.0160} .4080+.0113| 7.5386+.0216| .4130+.0152|— .0407+.0268]— .0050+.0189 
proportions, 
Dactenreer 78.2301 .1125) 2.8388+.0795| 78.0361+.1497| 2.8594 .1058]-+ .1940+.1872]— .0186+.1323 
Length aperture+ 
length shell, propor- 
TIONS ED ACU Ene 52.0467 + .0785} 1.9788 .0555| 52.1144 .0929) 1.7756+.0657| — .0677+.1216| + .2032+.0860 
CoMPARISON OF THE CoLoR-CLASSES. 
It is unnecessary to add materially to the statements made earlier regarding 
the varying proportion of sinistral and dextral specimens belonging to the several 
color-classes. Banded examples occur here with both modes of coil; in Fautaua 
the only specimens of this pattern were sinistral. The full statistical description 
of the several subdivisions is given in table 69. Aside from the difference between 
the direct and the reversed classes of shells, already dealt with, the most striking 
point is that the banded specimens are quite peculiar, as compared with the plain 
shells of corresponding twist. 
