PARTULA OTAHEITANA. 229 
In fertility at the time of collection (the drier season of 1907) an average degree 
is indicated (table 172) except for the phea class, which falls below the others; the 
numbers are too few, however, to give a basis for a definite statement as to the 
existence of differential fertility. 
The data of heredity (table 172) are particularly interesting in view of what 
was discovered further west. Apex adults produce young of all three kinds, with 
their own type in greater abundance. The same may be said of the cestata class. 
But the single embryonic shell taken from a phea adult was an unmistakable apex. 
The total number of phea among the young 1s greater than in the series of gravid 
adults; this may point to a secular change in the color-complexion of the colony 
as a whole, or it may be something that would disappear if more observations 
were at hand. In any case the genetic interrelationships of apex, cestata, and phea are 
manifest. 
TasBLe 171.—Partula otaheitana sinistrorsa. Apirimaue Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
3 = ture + length 
Seriests ||PNON|s-s ea eee hall, wane 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm, mm. p. ct. p. ct. 
apex....| 16) 19.5000+.1214) 10.8125+.0942) 55.3750+.2139| 9.8000+.1309| 7.2250+.0799| 73.8750+ .4577) 50.2500+.3010 
cestata ..| 264! 19.3988+.0407| 10.6939 .0208) 55.0606 .1009| 9.5983 = .0202| 7.1810+.0155} 74.8637 .1106] 49.3334 .0763 
phea.... 4) 18.6500 .1430) 10.5500 .0292) 56.7500 .6021| 9.4500+.0735) 7.0000 .1012) 74.0000 +1.2952) 50.5000+.0 
Alle. 284) 19.3926+.0371) 10.6993 = .0200) 55.1021 += .0953) 9.6042 .0198) 7.1810+.0152) 74.7958 .1080) 59.4014 .0737 
STANDARD DEVIATION. 
apex..... 16 0.7202 +.0858| 0.5588 .0666| 1.2686==.1512) 0.7762+.0933) 0.4737 0565| 2.7146 .3236) 1.7853+.2128 
cestata.. .| 264 -9765 = .0288 -5003+.0147} 2.4301+.0713) .4862+.0143 .3745 0100! 2.6638 .0782) 1.8388+.0539 
phea. J6'6 4 4242+ .1011) -0866+.0206| 1.7853 .4257| .2179+.0520) .3000+.0715| 3.8406 .9158) 0 
== | ee ee ee Se 
ALS 284 -9265 = .0262 .5008=.0141} 2.3812+.0674| .4949=.0140) .3806+.0107| 2.6979 .0764| 1.8397+.0521 
TaBiLe 172.—Partula otaheitana sinistrorsa. Apirimaue Valley. 
| 
FEcuNDITY. | HEreEDITY. 
Serie Records No. of | Per cent} No. of | No. of Total Average | Average | Young| Young | Young Total 
= ‘| gravid.| gravid. | eggs. | young. | contents. |for gravid. for all. | apex. | cestata. phea. Ore: 
| | | 
apex ages 16 13 81.2 16 11 27 2.07 1.69 | 7 1 3 11 
cestata.... 247 217 87.8 288 157 445 2.05 1.80 4 151 2 157 
phaser 4 3 75.0 3 1 4 1.33 1.00 | 1 fe 1 
ATS ost 267 233 87.3 307 169 476 2.04 1.78 | 12 152 | 5 169 
Tiravirt VALLEY. 
With this valley we enter a region where dextral representatives of sinistrorsa 
appear in substantial numbers; here they amount to about one-third of the whole 
otaheitana collection. 
The reversed shells fall into the three established color-classes (plate 30, figs. 
36 to 38, 40 to 44, and 46), of which both apex and phea are more numerously 
