206 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
THE NORTHERN TAIARAPU COLONIES—TEHORO AND HAAVINI VALLEYS. 
TEHoRO VALLEY. 
Instead of rounding the southeastern point of the island, we may pass from 
Faone to the northern side of Taiarapu, where in Tehoro and Haavini a novel type 
of coloration is met with, and where the dubia and zonata forms are lacking. Among 
the shells of the former colony (plate 29, figs. 54 to 59) 18.3 per cent are bicolored 
(figs. 57 to §9); that is, the right half of the body-whorl which adjoins the spire is 
lighter brown and the left half is darker in color although the difference between 
the two sides is not always very evident. The suture between successive whorls 
coincides very nearly with the median plane on which the color divides, but there 
is a slight darkening above the suture of the penultimate whorl that indicates a 
continuity of the bicolored pattern part way into the spire. ‘Two of the 15 adoles- 
cent shells show this double coloration, but it does not appear in any of the embry- 
onic individuals; hence we must conclude that it is developed only during later 
growth, if at all. The peculiar type is distinguished as the color-form anomala. 
A few of the plain shells from Tehoro exhibit a red or pink color (plate 29, figs. 
55 and 56) that recalls the notable feature of the Farapa colony. Such individuals are 
light-yellow otherwise, and belong to the first of the three distinguishable classes, 
viz, light, medium, and dark. In statistical respects (table 146) these three groups 
and the anomala class agree closely and they are collectively smaller than the shells 
of the nearest valleys in the eastern sector. 
The statistics of fecundity are high (table 147) and remarkably uniform 
throughout the colony. Combining the plain and parti-colored parents and classi- 
fying them according to the intensity of the ground-color, the figures relating to the 
inheritance of the depth of color (table 147) give an excess of medium young and 
a deficiency in the dark class. Presumably the deep-brown coloration is attained 
only later in life by some individuals that have medium-brown shells as embryos. 
TaBiLe 146.—Partula otaheitana affinis. Tehoro Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
Series. No. shah ees - Tooth, index. 
Length. Width. Proportions. Length. Width. Proportions. fies 
mm. mm. p. ct. mm. mm. p. ct. Dp. ct. 
Plain, yellow....... 100) 15.9740+ .0484, 9.4380+.0217| 59.0300+.1512) 8.4780 .0241| 6.4540 .0193] 75.9000 .1520} 52.9800==.1295| ............ 
yellow brown.} 55| 16.0591 .0639 9.4746+ .0271) 58.8636+.2069| 8.5255+.0292) 6.4782 + .0244| 75.9909+.1750) 53.0091+.1673) ............ 
IDEOWN rye 92) 16.0381+.0463} 9.4044+ .0253) 58.5761+.1364) 8.4500 .0280) 6.4565=+.0211] 76.3696+.1653) 52.5652+.1286) ............ 
Plainwallepaeretertrts 247| 16.0168 .0298) 9.4336+.0142) 58.8238 .0923| 8.4782+.0157| 6.4604 .0124| 76.0952+.0958) 52.8319 .0808) 3.3253+.0307 
Half-banded....... 56| 16.0786 .0627| 9.3608 .0274| 58.1608-+.1780| 8.4893+.0256| 6.4608+.0242| 76.0000 .2462| 52.7678 .1440) 3.2142+.0531 
/Aligomiocanadso0Doo 303} 16.0282=.0259| 9.4201+.0128) 58.7013+.0828) 8.4802=.0137| 6.4604 .0096| 76.0776+.0904| 52.8201=.0713) 3.3049+.0330 
STANDARD DEVIATION. 
Plain, yellow....... 100} 0.7183+.0342) 0.3221+.0153) 2.2425+.1069} 0.3576 .0170} 0.2868 .0136) 2.2538=.1075| 1.9208=.0915) ............ 
yellow brown.} 55 .7024= 0452) .2980+.0191; 2.2753+.1463) .3215+.0206| .2688+.0172) 1.9247+.1236| 1.8377+.1183] ............ 
brown....... 92 .6584+ .0346| .3606+.0179| 1.9406+.0964) .3985=+.0198} .3004+.0149| 2.3508+.1169) 1.8285+.0909) ............ 
Plainwallercerenierict 247 .6942 + .0211) .3330+.0100) 2.1522+.0652) .3671=.0111) .2884+.0088 2.2329 + .0677| 1.8798 .0571| 0.7188 .0217 
Half-banded....... 56 .6963 = .0443) .3046+.0194) 1.9755+.1257) .2839%.0181| .2684+.0171) 2.7321+.1741) 1.5983+.1018] .5890+.0375 
AL ekshovevarstersieietereleye 303 -6680+.0183} .3291+.0091) 2.1362+.0585) .3533+.0097| .2471+.0068| 2.3335+.0639) 1.8401+=.0504| .6981+.0233 
1The numbers are, respectively, 249, 56; 305. 
