128 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
It will be recalled that the series of 1906 was taken in February and March, 
toward the end of the rainy season, while that of 1907 was secured in June, and the 
smaller lot of 1908 in September. ‘Taking these series as typical of the whole 
population, a distinct rise in the rate of productivity occurs with the progress of 
time from the early months to June and to September. Such facts indicate that 
the breeding-season in this valley begins with the heavier rains, when the greater 
amount of moisture stimulates the snails to increased activity in every functional 
respect. 
HEREDITY. 
We come at last to the highly interesting statistics of heredity, to which passing 
reference has been made at one or another point in the foregoing description. The 
figures are given in full and in summary in table 64. Naturally, it is difficult 
TasLe 64.—Partula otaheitana otaheitana, Fautaua Valley. 
Fut. Sratistics or HEREDITY. 
Color-class, sinistral, young.) Color-class, dextral. young. 
Form and color-classes, adults. 
IV. ; II. 
Sinistral, plain, 
Sinistral, bands 
Sinistral, all 
Dextral, plain, 
HEREDITY OF COLOR-CHARACTERS. HerepIty oF Col. 
Young, plain. Young. 
III.) IV. Sinistral. Dextral. 
Adults: 
Sinistral.... 204 85 289 
[56.22 p. ct.] 
225 
Dextral. ... 49 176 
[43.77 p. ct.] 
Total... 253 261 514 
[49.22 p. ct.]| [50.77 p. ct.] 
