PARTULA OTAHEITANA. 223 
shell is the third band, which is more frequently vague as to its limits. The lip is 
usually stained with brown or purplish brown. Some suffusion of the bands takes 
place on the last whorl in many instances, although the markings retain their integ- 
rity on the spire. The shell shown in figure 15 is in color an exact counterpart of 
Pilsbry’s figure 1, plate 26, assigned to amabilis; it has been shown earlier that 
amabilis is never banded and that such shells are true sinistrorsa. Decortication 
leads to the whitening of the ground-color, as in figure 13. The third color-class, 
pha, comprises a few shells that are an almost uniform deep chestnut-brown (plate 
30, figures 17 and 18) and have the lip tinted with brown or purple-brown, like the 
cestata shells. Pilsbry has given the name confluens to a color-form of sinistrorsa 
which occurs in some of the southern valleys in Tahiti nui; the type existing here 
somewhat resembles confluens, but its uniform and “solid” ground-color is not due 
to the merging of the revolving bands or of vague strigations, but is sui generis. 
When in later pages it becomes necessary to employ a distinctive name for this 
particular kind of phza, it will be distinguished as phea solida; until then it will be 
understood that shells assigned to phea are of this subordinate class. 
TasBLe 162.—Partula otaheitana sinistrorsa. Vaiaaia Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
Saag, |l ii ture + length 
shell, propor- 
Length. Width. Proportions. Length. Width. Proportions. tions. 
‘Fares | | 
mm. mm. p. ct. mm. mm. p. ct. p. ct. 
apexeeere 55} 20.1446+.0672) 11.1546+.0401) 55.3182+.1978) 10.3582+.0424) 7.7618 .0362| 74.7546+.2478) 51.3909=+.1669 
cestata 77| 20.0955 == .0586) 11.2611 + .0349| 55.9285+.1509) 10.4871 + .0318) 7.8559+ .0263) 75.0065 .1897| 52.1571 .1113 
phea. 5} 20.3300 +.1354) 11.3400+.1396) 55.5000+.3815) 10.4200+.1645| 8.0626+.0926) 77.1000+.9462| 51.5000+.5594 
INS Goac 137| 20.1237 + .0430) 11.2212 .0260| 55.6679 .1183) 10.4328 .0257| 7.8255=+ .0212| 74.9818 .1519) 51.8212 .0962 
STANDARD DEVIATION. 
aDeXerrere 55} 0.7391+.0475| 0.4406+.0283) 2.1749+.1398 0.4666-*.0300 0.3979 .0256) 2.7251.1752) 1.8357.1180 
cestata...| 77 .7625 += .0414 4536+ .0248} 1.9629=.1067 4144+ 0225 3421 = .0186) 2.4686 .1341| 1.4485+.0787 
phea.... 5 4489 = .0957 .4630+.0987! 1.2649 .2698 9455 .1163) .3072+.0655| 3.1369=.6690} 1.8547+.3955 
SE a eee eee) | Saree meant ery) [nee eee! ea 
Ave ci 137 -7459== .0304) .4522+.0184) 2.0524+.0836 4459-0182} .3689+.0150) 2.6363+.1074| 1.6695+.0680 
At first sight, the form apex is much like rubescens shells which possess tinted 
spires, but on further acquaintance their distinctness becomes increasingly apparent; 
apex and phea are bandless, but they are probably no more intimately related to one 
another than either is to cestata. 
The shells of all classes are entirely devoid of a columella tooth. 
respects (table 162) the three groups are somewhat diverse, phea being the most 
The large dimensions of the shells and of their apertures are notable 
aberrant. 
features. 
In statistical 
Fecundity at the time of collection, August, was fairly high (table 163), with a 
somewhat lower rate for cestata than for the other classes. 
The data on heredity (table 163) are interesting because all of the young of 
cestata were banded; apex produced its own kind and cestata young as well, while phea 
