PARTULA OTAHEITANA. 225 
Fecundity in this series is high (table 165) and the larger numbers of embryonic 
young render the data on heredity (table 165) quite reliable. As in Vaiaaia, the 
cestata adults produce only their own kind; apex produces very few of its own type 
in comparison with the numbers of cestata young. It may be that there is a Men- 
delian order of inheritance in the case of the “plain” and the “banded” characters, 
in which case the large numbers of banded young would indicate that the cestata 
character was dominant, and their apex parents would have mated with DD or DR 
banded cestata individuals. It is possible that a secular change in the direction of 
an entirely banded population is taking place; to settle this point collections should 
be taken at successive intervals of years. 
TaBLe 165.—Partula otahettana sinistrorsa. Aravaro Valley. 
FEcunNDITY. HeERepity. 
2 No. of | Per cent} No. of | No. of Total Average | Average |} Young,| Young, 
Series. Records: gravid.| gravid. | eggs. | young. | contents. | for gravid.| for all. apex. | cestata. Total. 
ADEXG ats eererersr taro 37 30 81.1 40 24 64 9318} 1.73 3 21 24 
cestatal cacuraeicreia- 133 120 90.2 142 114 256 Diels 1.92 ie 114 114 
IMU ee ooo Gono oon 170 150 | 88.2 182 138 320 Deals 18 i} 8 135 138 
Vavil VALLEY. 
Collections were secured in this valley during two different seasons, in different 
years. They were taken from the same part of the small valley and agree in 
their make-up, though not in the rate of productivity. Taken together, they are 
remarkable in being composed solely of cestata shells, although the distinctness of 
the markings varies considerably; apex like phea is entirely lacking. 
The shells fall into three subordinate sections within the cestata limits. First 
and most abundant is the completely and distinctly banded type which has been 
seen earlier (plate 30, fig. 26). Next there are many which possess the banded spire, 
but have the bands evanescent on the basal whorl (plate 30, fig. 25). Third, there 
are some which have markings only on the first and second apical whorls, below 
which the yellowish-horny ground-color is displayed, with few or many fine stri- 
gations of a “transverse” nature (plate 30, fig. 24); such shells might readily be 
mistaken for darker relatives of apex or lighter counterparts of phea. The adoles- 
cent shells fall into the same groups, although the distinctly banded individuals far 
outnumber the others, which is only natural in view of the fact that the stripes fade 
out only on the later-added coils. 
Statistically, the Vavii shells are large and somewhat narrowed (table 166). 
The group of nearly plain shells is shorter than the others, and somewhat stouter, 
because the width is not greatly diminished. All are devoid of the columellar tooth. 
The material of the hot and wet season of 1906 shows a low rate of reproductive 
activity as compared with that of 1907, taken during the season of less heat and 
humidity (table 167); the latter compares favorably with the series of Vaiaaia and 
Aiavaro. Obviously the close of the rainy season witnesses a resumption of breeding 
on the part of a large proportion of the snails. 
