PARTULA OTAHEITANA. 157 
The detailed facts (table 95) give affirmative answers to both questions, but 
in the second case a qualification is necessary; both classes change, but to diverse 
degrees. In the 1906 series, the yellow shells are collectively smaller than the red 
ones in all four absolute measures, in two of which they are certainly different; and 
they are narrower in shell proportions. Exactly similar relations obtain in the 1908 
series, although the differences are not so large as compared withtheir probable errors, 
except in one case. But the 1909 series shows no such relation; indeed, in two or 
three characters it is entirely reversed. The facts may be stated in another way: 
the yellow shells of successive years—and localities—at first become smaller (1906- 
1908), and then larger (1908-1909), but the red shells become smaller with some 
significance in both cases; because the yellow shells are more abundant relatively 
in the last year’s collection—inner locality—their increase in size in the second 
step—1g908 to 1909—masks the change in the red type when the figures for the 
combined classes are compared, as in table 94. In a word, the reduction in size of 
the whole series of 1909 can not be attributed to a greater proportion of small red 
individuals. ‘Thus the more detailed analysis of the color-classes brings to light 
most important relations which otherwise would have been undisclosed. 
TaBLe 96.—Partula otaheitana rubescens, Papenoo Valley. 
SraTisTics OF FECUNDITY. 
No. of | Per cent No. of No. of Total Average | Average 
gravid. gravid. eggs. young. | contents. | for gravid.| for all. 
MQ)5 o00000 49 24 48.9 19 15 34 1.41 0.69 
1. Soocee 89 75 84.2 106 119 225 3.00 Dio 2 
1909 Fert 173 157 90.7 327 174 501 3.19 2.89 
311 256 452 308 760 
ComMPaRaTIVE FECUNDITY: YELLOW AND Rep. 
No. of Total Total Average | Average 
gravid. | contents.| young. | contents. young. 
Mellow #l90Gi Frei forsee ee else oan 9 13 4 1.4 0.4 
LE iocoiaeo eae Hic OOo Oo Corio Chere 17 49 22 2.9 1.3 
LOO Dei vacore saree lots wee Beare a Oe eae 63 200 66 Soil 15 
hiellow alleen vse ae eae 89 262 92 2.9 1.0 
FR CCL OG erste rey ebe tate ber sheYoi efoto ih ses aierads 15 21 11 1.4 0.7 
OOS erty eel ehares chore ota: he oetamen 58 176 97 3.0 ibs 7/ 
LO aoe OD OO ORICA omee Gote 94 301 108 So i} 14 
Rec Stall Ray stapatspores orev vovenesetanclovecesct cxsnshepotorn havoke 167 498 216 2.9 11.8} 
In fecundity, the first series is very low (table 96), while those of 1908 and 
1909 agree in a relatively high rate. The first series was taken during the early part 
of the year, and the other was secured during the middle months. Apparently the 
hotter and wetter season witnesses the initiation of renewed reproductive activity. 
The comparative fecundity of yellow and red shelled snails is a matter of some 
consequence in connection with a later point. The figures for the three annual 
series (table 96) prove that the general rate of fecundity is practically the same 
