144 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
The distinctive features of this colony, as compared with that of Pirai, are: 
(1) the reduced size; (2) the lack of the reddish color-tones; and (3) the occurrence 
of numerous dark-brown individuals, which, although sinistral, approach the typical 
condition of the dextral P. otaheitana affinis. 
TasiLe 78.—Partula otaheitana amabilis, Pohaitara Valley. Comparison of the color-classes. 
MEAN VALUE. 
Shell. Aperture. Length aper- 
Series. | No. SEO aman 
shell, propor- 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm. mm. p. ct. p. ct. 
Light. 64 | 17.4078+.0740| 10.5187 + .0386) 60.3125+.1999) 9.2750+ .0424) 7.1750+.0317| 77.4063 .2189) 53.1250 .1559 
Medium.| 182 | 17.6181 .0394| 10.4682 + .0233} 59.3517 .1000) 9.2308 .0200} 7.1956=.0190} 77.5456+.1325 52.3517 + .0933: 
Dark. 133 | 17.5560 .0428) 10.4880 .0248) 59.6504 .1968} 9.2895 = .0231| 7.2023 .0212| 77.4474+.1734| 52.6504+.1091 
INU ssid. 379 | 17.5608 .0273) 10.4836 .0156| 59.6187 = .0683)] 9.2588+.0144| 7.1945 = .0130) 77.6847 + .0984| 52.5871 + .0639 
STANDARD DEVIATION. 
Light. 64 0.8776 .0532| 0.4579=+.0273} 2.3709=.1413) 0.5031 .0300) 0.3766+.0224) 2.5964+.1548) 1.8498+.1102 
Medium.| 182 -1877 + .0278 .4656+.0165| 2.0011+.0707| .4003+.0141| .3807+.0134| 2.8406+.0937| 1.8659+.0560 
Dark. 133 .7322 += .0302 4248+ .0175| 2.2661+.1391) .3949+.0163} .3626+.0150) 2.9642+.1226] 1.8658+.0771 
Ae 379 -7885 = .0193 .4508+.0110} 1.9720+.0483] .4164.0102| .3738+.0092| 2.8401+.0696} 1.8435+.0452 
TaBLe 79.—Partula otaheitana amabilis, Pohaitara Valley. Statistics of tooth-development. 
Series No No tooth.| Trace.] Tooth. | Large.| Very large Mean value SAC 
; 4 . j : i deviation. 
Wighteeeeee 65 10 14 36 5 iv 2.5539 .0704 0.8418+ .0498 
Medium....| 188 22 50 99 14 3 2.6064 .0416 . 8470+ .0294 
DMarkeveveey. 134 14 26 80 12 2 2.7165+ .0481 . 8251+ .0340 
A epee vers 387 46 90 215 31 5 8408+ .0203 
Average for growth 
Average for all 
HEREDITY. 
Light. 
URUROA VALLEY. 
Ururoa Valley, like Pohaitara, is a relatively shallow gully of steep gradient. 
It lies nearest to the main ridge or backbone of the mountain mass between Pirai 
and Tuauru Valleys—the spine, namely, that terminates at the steep bluffs of 
Valley. 
Medium. | Dark. 
Total. 
