PARTULA OTAHEITANA. I4I 
again the same diminution, in a third instance. In brief, the changes observed 
are consistently displayed by all the groups that are sufficiently numerous to 
give satisfactory statistics, and the class differences of a given year are secondary 
in importance in this connection. 
TaBLe 75.—Partula otaheitana amabilis, Pirai Valley. Analysts of the color-classes of 1907 and 1909. 
Mean VALUE. 
Shell. Aperture. Length aper- 
‘ ture + length 0 
Series. | No. shell! propor: Tooth, index. 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm. mm. p. ct. p. ct. 
1907, I.| 157 | 18.2905+.0511| 10.7242+.0244| 58.3726+.1164| 9.4962 .0264| 7.4032 .0218) 77.9331 .1324| 51.6592 .0958| 2.8144 .0373 
Il.| 75 | 18.4960+.0816| 10.7294 .0362| 57.8066 .1980) 9.5187 .0355| 7.4360 .0293| 78.2333 .2058) 51.2200 .1450| 2.8049+ .0599 
IIl. 1 | 18.9500 10.3000 + 54.5000 9.5000 7.6200 = 76.9000 50.5000 3.000 
1907, all. .| 233 | 18.4092 =+.0428| 10.7243 + .0203] 58.1738 .1017| 9.5035 + .0213) 7.4116 .0175| 78.0021+.1128) 51.5129 .0801| 2.8120+.0298 
1909, I.) 296 | 17.7881+.0337| 10.4372+.0179| 58.4966 .0891 9.2169 .0181) 7.1845 + .0152| 77.9966 .1188) 51.6148 .0696| 2.9672+ .0311 
II.| 47 | 17.7319+.0903) 10.4106 .0439) 58.5000 + .2595) 9.1298 .0431) 7.1085 .0382) 77.5212+.3091) 51.2234 .2057| 2.8776+.0572 
Ill. 5 | 17.9400 .4968) 10.4600 = .2235| 58.3000+.7958) 9.3000+.2778) 7.3400+.2104) 79.1000+.4901| 51.7000 .3518) 2.4000+ .2413 
IV. 1 | 19.2500 10.9000 58.5000 9.8600 7.6600 75.5000 49.5000 2.8000 
1909, all..| 349 | 17.8368 .0320) 10.4352 .0167) 58.4942 + .0840} 9.2072+.0170) 7.1768+.0147| 77.9412 .1095| 51.5573+.0657| 2.9417 + .0286 
STANDARD DEVIATION. 
LOO (ema Lis | 1517, 0.9458+.0361) 0.4533+.0172) 2.1436+.0821) 0.4912+.0187| 0.4061+.0154| 2.4605+.0936) 1.7792+.0677) 0.7144 .0265 
II.} 75 1.0467 = .0577 4774 .0256| 2.5402.1401) .4677+.0251) .3755+.0207| 2.6393+.1455| 1.8587=+.1025) .6704+.0423 
1907, all. .| 233 -9689 = .0302 .4607 = .0144) 2.3024=.0719| .4829=.0151| .3973+.0124) 2.5541=.0798 1.8139 .0566| .6990 .0211 
1909, I.| 296 -8593 + .0238 4582+ .0119) 2.2723+.0630) .4632+.0128) .3891+.0107| 3.0302+.0840) 1.7745+.0492) .8050+.0220 
II.| 47 -9183 + .0638 4458+ .0310) 2.6377+.1835] .4385+.0305) .3869=.0270} 3.1318+.2185} 2.0905+.1454 .5936+.0404 
Ill. 5 1.6470 .3513 -7411+.1580| 2.6382+.4920) .9209+.1964) .6974+.1488) 1.6248+.3465] 1.1662+.2487| .8000+.1706 
1909, all. .) 349 .8862 + .0226 .4620+.0118] 2.3284+.0594| .4704+.0120) .4082+.0104| 3.0346+.0774| 1.8190+.0464| .8058+.0202 
FECUNDITY. 
In reproductive ability (table 76) the several annual series are alike to a degree 
that is remarkable in view of the differences in the seasons of their capture. Nearly 
70 per cent of the snails taken in the wet season of 1906 were bearing, while only 
50 per cent of the 1909 collection, secured during the dry season, were fertile. The 
eggs are fewer in proportion to the number of young, in the former case, and it would 
seem that about the beginning of the dry season the snails began upon a new period 
of reproductive activity. Nevertheless, no generalization is justified on the basis 
of the observations on the snails of a single valley taken at such widely separated 
intervals of time. 
HEREDITY. 
On account of the faint coloration of embryonic shells, their exact classification 
on a color-basis is difficult. The statistics of heredity, as given in table 77, may 
not be entirely trustworthy, but they show conclusively that the banded character 
appears in offspring of plain parents, and that banded adults produce both kinds 
of young snails. The members of Class III contribute light-colored young to 
