PARTULA OTAHEITANA. 277 
As regards fecundity (table 232) the Aoua snails displayed an average degree 
of reproductive activity, while the Papehue collection of the same time and year 
(1907) gave astonishingly low figures, both of gravid individuals and of average 
contents. Unfortunately the data for the 1906 series from the latter valley are 
scanty, but they also indicate a low rate of productivity. 
The data of heredity (table 233) are particularly valuable for two matters of 
importance, namely, the relation of the yellow and red color-classes to one another 
and the relation of the brown class to the prevalent types. The figures show that 
the yellow and red forms interbreed and that the relative numbers are essentially 
the same among the young and among the parents. A yellow-shelled snail of Aoua 
bore one young with a yellowish-brown shell; this is probably phza. 
TaBLE 233.—Partula otaheitana crassa occidentalis. 
Herepity, Aoua VALLEY. Herepity, PAPEHUE VALLEY. 
Young, Young, Total Young, Young, 
yellow. red. yellow. aK. Total. 
Conducting an analysis of the color-relations between parents and offspring, 
to ascertain whether a Mendelian order of inheritance is followed, the characters 
in question, as well as the problems, are precisely the same as in the case of P. o. 
rubescens. We may ignore the few phea individuals, and deal only with the numerous 
yellow and red members of the Aoua colony. In the general population, the former 
amount to 304 out of 645, or 47.1 per cent, and the latter to 341, or 52.8 per cent; 
these are basic data. 
Proceeding first on the assumption that the red color is dominant, the gravid 
adults with distinguishable young are classified as follows: 
(1) Red adults: red young, 51; red and yellow young, 12; yellow young, 19 =82 
(2) Yellow adults: red young, 25; red and yellow young, 5; yellow young, 60=90 
The yellow parents would have mated with DD, DR, and RR snails according 
to the chance possibilities, of which the last is known, inasmuch as the group 
assumed to be RR—viz, those of (2)—constitute 47 per cent of the population at 
large. Hence the combination RR X RR would occur in 47 per cent of the go cases, 
or 42, and these would bear yellow young only. Actually, however, there are 60, 
and hence the excess over 42, or 18, comprises the RR XDR cases where too few 
offspring appear to represent both of the expected kinds. Transferring the 18 such 
cases to the middle class, and a similar proportionate number (#5 of 25 or 7.5) from 
the first to the second group, for similar reasons, (2) becomes 
(3) Yellow adults: red young, 17.5; red and yellow young, 30.5; yellow young, 42=90 
and the proportionate numbers of DD, DR, and RR snails thus become defined. 
