PARTULA OTAHEITANA. 
Tas ie 58.—Partula otaheitana otaheitana, Fautaua Valley. 
Sinistral [506]. 
125 
Comparison of unbanded sinistral and dextral shells. 
Dextral [421]. Differences. 
Mean value. 
Standard 
deviation. 
Mean value. 
Standard 
deviation. 
19.0958 + .0268 
10.9870 + .0140 
57.4269 + .0794 
0.8943 = .0190 
-4664+ .0099 
2.6485 = .0562 
19.3184 .0304 
10.9736+.0172 
56.7447 = .0745 
0.9263 + .0215 
-5219+ .0122 
2.2660 + .0527 
Mean value. 
—0.2226+.0405 
+ .0034+.0221 
+ .6822+.1089 
Standard 
deviation. 
—0.0320 + .0287 
— .0545 = .0157 
+ .3825+.0770 
9.8312 + .0143 
7.7245 + .0116 
78.4862 + .0819 
Aperture, length, mm 
proportions, p.ct.... 
-4768+ .0101 
-3856 + .0082 
2.7326+ .0579 
9.8853 + .0163 
7.6667 + .0130 
77.4976 = .0937 
-4969 + .0115 
-3943 = .0092 
2.8505 + .0663 
-0541 + .0216 
-0578+ .0174 
-9886 + .1244 
“+ 
+ 
-0201+ .0153 
-0087 + .0123 
-1179+ .0880 
Length aperture + length shell, 
proportions, p. ct 51.4130 .0593 
1.9772 .0419 
51.1176+.0644 
1.9595 + .0455 
COMPARISON OF THE COLOR-CLASSES. 
The object of this comparison is to ascertain whether differentiation in dimen- 
sional respects accompanies that which is expressed in general ground-color or in 
the matter of the banded coloration. 
late directly and significantly with this comparison. 
The absolute and proportionate numbers referable to the several color-classes 
are given in table 60, already noted in an earlier connection. 
-2954 .0875 
.0177+.0618 
The later study of the Pirai snails will articu- 
There is nothing here 
that is indicative of a definite and consistent hereditary predisposition in any class 
in favor of one or the other mode of coil. 
TaBLE 60.—Partula otaheitana otaheitana, Fautaua Valley. 
Numerical relations of the color-classes. 
Number plain. Per cent plain. 
Sorina No. Number __| Per cent 
Class | Class | Class | Class isexneteel Class Class Class Class banded: 
Is Il. elke IV. I. Il. Ill. IV. 
Sinistral, 1906....... 229 47 34 111 37 Se 20.5 14.8 48.4 16.1 Sac 
IMMoccoocd| ZW 46 41 116 27 6 20.0 17.8 50.4 ii at 
1908....... 67 11 12 29 12 3 16.4 17.9 43.3 17.9 4.4 
Dextral, 1906....... 191 36 40 87 28 18.8 20.9 45.5 14.6 
NOOR a 176 29 31 95 21 16.5 17.6 53.9 11.9 
MOOSE sete 62 14 6 32 10 22.6 9.6 51.6 16.1 
Siniieall alll, coococc 526 104 87 256 76 3 19.8 16.5 48.7 14.4 0.5 
Wextralwalleenn. 4). 429 79 77 214 59 18.4 17.9 49.9 NG o es 
PROtAL ON ys es 955 183 164 470 135 3 19.1 ile ott | 49.2 14.1 0.3 
We come now to the statistics relating to the seven standard characters of 
the shell, together with the eighth quality of tooth development (tables 61 and 62). 
The first general result is that the three-banded and sinistral shells are statistically 
different from the plain or unbanded examples. Specifically the former, as compared 
with the contrasted sinistral group, are as follows: 
Shell, length in millimeters 
width in millimeters 
proportions (per cent) 
Aperture, length in millimete 
width in millimeters 
proportions (per ce 
Tooth (index) 
ts 
nt) 
Length aperture + length shell, proportions, per cent 
—0.0912 
—1.9862+1. 
—0.9130+ 
--0.2879+ 
3449 
. 1109 
.6000 
. 1841 
.0385 
1044 
3235 
0664 
