PARTULA OTAHEITANA. 271 
In fecundity (table 225) at the time of collection, the figures for the several 
groups are sufficiently alike to render the occurrence of differential fertility im- 
probable. 
All of the 149 young were sinistral, unbanded, and light or medium brown in 
color. The faintness of the band even in the adults, when present, together with 
the above, would indicate that the distinctive markings of the cestata shells are 
developed only in postembryonic life. In this connection we may note that only 
2 among 37 adolescents, or 5.4 per cent, showed a band, as compared with 7.5 per 
cent cestata among the adults. 
ATITARA VALLEY. 
In this region the crassa association agrees in all essential respects with the 
colony of Vaitupa, saving only that one dextral mutant of plain coloration was found 
in a series of 154 adults and 17 adolescents. The principal color-types are repre- 
sented as follows: 
Per cent. 
phe striata, sin 
pheza confluens, sin 
cestata, sin 
pheea striata, dex 
The notable points are the greater number of banded shells and the smaller rela- 
tive numbers of phea confluens. In addition to the dextral mutant (plate 33, fig.21) the 
illustrations show shells of unusual form or size or color (plate 33, figs. 16 to 20). 
TABLE 226.—Partula otaheitana crassa. Atitara Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
Series. No. ture + length Tooth, index. 
shell, propor- 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm. nm. p. ct. DaCle 
Plain, sin... .| 135) 16.6523 .0452) 9.7074 .0234| 58.1444+ .1286| 9.0082 .0273] 6.7741+.0210) 75.1222+ .1336| 53.9444 .1130) 2.7333 .0475 
Banded, sin..| 18] 17.0667+.0924) 9.7556+.0447| 57.0556 .2760| 9.0889= .0575| 6.8000+ .0465] 74.4445 + .3287) 53.1111+.2957) 2.7778+.1131 
Al Sineeee 153} 16.7206 .0426] 9.7131+.0214} 58.0163 .1196) 9.0176 .0251| 6.7771+.0193) 75.0425+.1247| 53.8464+.1066| 2.7386 .0440 
Plain, dex... 1) 16.25 9.50 58.50 9.30 6.90 73.50 56.50 3 
STANDARD DEVIATION. 
Plain, sin....| 135) 0.7782 .0320) 0.4039 .0165|} 2.2160+.0909} 0.4706+.0193) 0.3617+.0148|] 2.3025+.0945] 1.9462+.0799] 0.8183 .0336 
Banded, sin. .| 18 -5814+ .0653] .2813+.0316) 1.7362+.1952) .3619+.0406) .2925+.0329| 2.0675 .2324| 1.8601+.2091| .7114.0800 
oe ee | ae | EE EE eee eee eee eee 
USI 153 -7805+ .0301) .3918+.0151) 2.1936+.0846) .4599+.0177) .3543+.0137 De ee 1.9547 .0754| .8066=.0311 
different from the rest in length and in the several proportionate measures. 
On the basis of the statistics (table 226) the banded group proves to be decidedly 
Indeed, 
the departures are difficult to understand unless there is some degree of selective 
mating. On the whole, the shells are far smaller and more tightly coiled than in 
Vaitupa. 
The tooth attains a greater degree of development as a colonial feature. 
