226 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
All of the embryonic young, 141 in number, were banded more or less distinctly 
but always noticeably. Hence there is further proof that apex and phea do not exist 
in this valley. 
TasLe 166.—Partula otaheitana sinistrorsa (cestata). Vavii Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
ae ee A ee a ee ee ee Pre. -lencth 
Group. No: shell, propor- 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm. mm. p. ct. Dp. Ct. 
Faint spirebands| 19) 21.0184 .1754) 11.3684 .0588) 54.5526+.3495) 10.6158 .0799| 7.9737 .0578) 75.0790 .3596| 50.3421+.1862 
Faint bands....| 64) 21.5000+.0751) 11.5125+.0477| 53.4438+.1828 10.6813+.0459| 7.9437+.0388| 74.3438 .1814| 49.6250+.1410 
Sharp bands....| 136) 21.4029+.0500) 11.4044= .0302) 53.2500 .1304) 10.6412 .0276| 7.8574 .0225| 73.8382 + .1485| 49.7206 .0992 
IN GoaooUdodS 219) 21.3979 .0428) 11.4416+.0236 53.4315 .1030 10.6507 +.0229| 7.8927+.0188) 74.0936=.1120) 49.7466=+ .0762 
| 
STANDARD DEVIATION. 
Faint spire bands} 19) 1.1335+.1240) 0.3798+.0416 2.2589 .2471| 0.5163+.0565| 0.3739 .0409| 2.3241+.2543] 1.2036+.1316 
Faint bands....| 64 -8908= .0531 -5655+ .0337|} 2.1679 .1292) -5451+.0324| .4602+.0274| 2.1522+.1283} 1.6724+.0997 
Sharp bands... .| 136 -8643 + .0353 .5219=+ .0213 gee te aees| A778+.0195| .3891=+.0159| 2.5673=.1050} 1.7157+.0701 
|e -9391.0302| .5179+.0167 2.2593 .0728 .5021+.0162) .4125+.0133) 2.4573.0792) 1.6726+.0539 
TasiLE 167.—Partula otahettana sinistrorsa. Vavii Valley. Fecundity. 
No. of | Percent! No. of | No. of Total Average Average 
Series. Records: gravid. | gravid. | eggs. | young. | contents. | for gravid. for all. 
VAIPOE VALLEY. 
In this small ravine sinzstrorsa exists in considerable numbers, while affinis, as 
we have seen, is very infrequent. The collections comprise 190 adult and 156 
adolescent snails of the former primary variety. The color-form phea is absent, 
as in Vavii and Alavaro. Apex appears, 14 out of 190, but with a modified appear- 
ance (plate 30, figs. 27 and 28); the larger whorls are marked transversely with fine 
and irregularly spaced strigations, so as to resemble lighter cestata individuals with 
attenuated bands. ‘The shells of the banded color-class cestata fall into the three 
subordinate groups recognized in Vavii (plate 30, figs. 29 to 35); the specimens figured 
are somewhat unusual ones, instead of average representatives. Of these three 
sections, the first comes to resemble the apex color-class, because the bandless 
whorls display similar strigations; hence it might seem that the shells called apex 
are really cestata with attenuation of the revolving stripes carried to its extreme. 
That this supposition is not correct, however, is clear from the comparison of 
adults and adolescents on the basis of the relative numbers assignable to the several 
color groups (table 168). Adolescents and adults of the apex class occur in about 
the same relative numbers, so that this class is sharply distinguished in the early 
stages. The cestata adolescents show a great preponderance of fully banded indi- 
viduals, as far as they have formed their shells; obviously the fading of the bands on 
the last-added whorls can not be noted until these whorls are formed, whereupon 
