238° VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
the colonies on both sides of this double valley have a positive development of this 
feature. 
The Vaihiria series was taken in March (1906) and that of Vairaharaha in 
June (1907), hence in different seasons. As would be expected, fecundity is rela- 
tively and absolutely lower in the former series (table 184). 
The data of heredity (table 184) are such as to signify a late development of 
the revolving bands in cestata. When 56 out of 57 young borne by banded parents 
from Vaihiria are plain, and 35 out of 39 from cestata parents of Vairaharaha are also 
unbanded, no alternative explanation is reasonable. Certainly it is not justifiable 
to regard the recorded observations as indicating a secular change in the direction 
of colonies made up solely of phea individuals. 
TaBLe 184.—Partula otahettana sinistrorsa. Vaihiria and Vairaharaha Valleys. 
FECUNDITY. 
j No. of | Per cent |} No. of | No. of Total Per cent | Percent 
Series. Records. ; : 5 
gravid.| gravid. | eggs. | young. | contents. | for gravid.| for all. 
Vaihiria, cestata........ 258 200 Wd oS 260 57 317 1.58 1.23 
Vaihiria, phea......... 23 20 86.9 27 7 34 1.70 1.48 
Waihitiasgal Sameer 281 220 78.3 287 64 351 1.59 125 
Vairaharaha, cestata.... 44 42 95.4 53 39 92 2.19 2.09 
Vairaharaha, phea..... 182 160 87.9 224 132 356 2.22 1.96 
Wairaharahaseal l Reeser 226 202 89.4 277 171 448 2.22 1.98 
Herepity. VAtmHiRIA VALLEY. HEREDITY. VAIRAHARAHA VALLEY. 
Young, Young, 
banded. plain. 
Young, Young, 
banded. plain. Total. 
Total. 
FAARAHI VALLEY. 
This valley runs parallel to Vairaharaha, from which it is well separated by a 
high and continuous spur of the mountain mass. In two different years journeys were 
made to this area; in 1907 Partula hyalina, P. clara, and P. otaheitana sinistrorsa 
were taken. In 1909 a close search was made for P. producta, and less attention 
was paid to the other species, but fortunately a representative collection of simzs- 
trorsa was obtained from the middle part of the valley, where it differs somewhat 
from the series of 1907, taken in the lower valley. 
The snails taken in 1909 were exclusively sinistral; those of 1907 were also 
reversed, with the exception of only two individuals. At first sight, the last-men- 
tioned specimens might be mistaken for P. producta, which was found in this valley 
and here only; but the resemblance is superficial, and disappears when the details 
of structure and color are taken into account. 
