PARTULA OTAHEITANA. 197 
The banded shells are especially interesting and peculiar. The red-striped 
group comprises (a) examples with very faint bands, sometimes only the median one 
being evident (plate 29, figs. 19 and 20); (b) others with separate though indistinct 
sutural, median, and basal markings (plate 29, fig. 21); and (c) a most novel series 
in which part of the last whorl is suffused with red, while the rest of it, like the spire, 
exhibits three bands as in (0d), (plate 29, figs. 22 and 23). In the division distinguished 
by brown revolving bands, the same subordinate types occur (plate 29, figs. 24 to 29) 
all the more clearly because the stripes are usually sharp and distinct; the 3-banded 
type anticipates dubia of later valleys. The terminal suffusion of bands is not an 
uncommon feature in other colonies of affinis, but there it is a prominent character 
of the colony, as it is not elsewhere, although it occurs also in certain associations of 
Partula otaheitana sinistralis from the other side of the island. 
When the several divisions are compared on the basis of their statistical char- 
acters (table 130) their substantial similarity is revealed. Certainly the plain and 
banded classes are alike in the morphology of the shell. Only the plain decorticated 
shells differ to an appreciable degree in absolute measures, but not in the propor- 
tionate figures; it is interesting to find a larger size associated with the physiological 
quality that results in the decortication of the surface during the later growth of 
the shell. 
Tas_e 131.—Partula otaheitana affinis erythrea. Farapa Valley. Fecundity. 
No. of | Percent | No. of | No. of Total Average Average 
Series. Records: gravid. | gravid. . | young. | contents. | for gravid. for all. 
.65 
94 
-98 
-02 
.88 
Plain, all ; 919 410 5 : .95 
Banded, all ; .99 
.95 
The fecundity of all groups (table 131) is well above the average. As the eggs 
greatly outnumber the advanced embryonic young, it would seem that reproductive 
activity had only recently been resumed at the time the snails were collected. 
Passing to the statistics of heredity (table 132), the first point to be noted is that 
the “whitish” adults bear yellowish or brown young, banded in only 1 out of 22 
cases, but none that displays the distinctive parent character. Plain adults produce 
unbanded as well as banded young of both color-types, and the banded adults also 
produce practically all kinds of young. A slight excess of plain young snails appears 
in the summary, which may indicate a small secular change in the proportionate 
numbers of the two primary classes of the succeeding generations, or it may be due 
to the difficulty of detecting the faint bands in the embryonic series of snails with 
small shells. In any case the positive observations remain that the various color- 
divisions of the Farapa colony breed true to their respective types in the main, and 
that they also contribute young to the other groups. 
