PARTULA OTAHEITANA. 275 
of the yellow members of rubescens colonies. Shells of the second class (plate 33, 
figs. 37 to 42, 48 and 49) are red, reddish-brown, or pink in a decorticated condition, 
and usually their colors are more intensely red on the spire. They do not grade into 
the seal-brown phza confluens type (plate 33, figs. 43 to 45), which are clearly discon- 
tinuous with them; the last are the only ones that are counterparts in all respects 
of typical crassa individuals from Orofere and other southward valleys. All shells 
are sinistral, and all display the nodosity of the columella margin of the aperture. 
The tooth is especially developed in the Aoua colony, thus giving an important 
contrast with rubescens, to which occidentalis is closely similar, save in size and in the 
plicated margin of the aperture. 
The statistics relating to the standard characters of the Aoua shells (table 230) 
indicate much similarity of the yellow and red classes, although some differences of 
possible significance appear. The brown shells, although few in number, depart 
consistently from their associates, in ways that suggest their genetic independence; 
their variabilities afford additional indication of their separateness. 
TaBLeE 230.—Partula otaheitana crassa occidentalis. Aoua Valley. 
Mean VALUE. 
Shell. Aperture. Length aper- 
vA ture + length : “3 
Series. No. shell, propor- Tooth, index. 
Length. Width. Proportions. Length. Width. Proportions. tions. 
mm. mm. p. ct. mm. mm. p. ct. Dp. Ct. 
Yellow. ..| 293) 17.1694 .0339) 9.9689 .0172) 57.9982 .0960| 9.1580 .0182) 6.9375 .0135] 75.6194 .0970) 53.2372 .0718) 2.7138+.0291 
Red...... 337) 17.1625 .0313) 9.9314 .0104| 57.7759 .0847) 9.1113 .0164| 6.8988 .0139) 75.6395 + .0982) 52.9926+.0721) 2.8006+ .0246 
Brown 5} 16.5500 .3082| 9.7000+.2055| 58.3000+.2257| 8.9400+ .1894| 6.7800+.1119) 76.1000+.6211) 53.3000 .3518) 2.8000+.2257 
PAU, fore revens 635] 17.1609 + .0230} 9.9469 .0116] 57.8827+ .0632) 9.1315+.0124! 6.9157+.0097) 75.6339 + .0689} 52.1078+.0519] 2.7600+ .0188 
STANDARD DEVIATION. 
Yellow...) 293) 0.8603+.0240) 0.4380+.0122) 2.4377+.0678) 0.4615+.0129) 0.3443+.0095| 2.4612 .0686) 1.8329+.0508| 0.7524+.0206 
Red iirs sree. 337 -8519=+ 0221) .2842+.0073) 2.3069+.0599| .4465+.0116) .3783+.0098| 2.6744+.0694) 1.9627+.0510|] .6729+=.0174 
Brown... 5} 1.0217+.2179| .6812+.1453) .7483+.1596} .6280+.1339| .3710+.0791| 2.0591 .4392) 1.1662+.2487| .7483+.1596 
PAN Eevenenere 635 -8590+.0163| .4332+.0082; 2.3631+.0447| .4633+.0088) .3637+=.0069 2.5741 = 0487) 1.9398 .0367,) .7131+.0133 
1The numbers are, respectively, 304, 341, 5; 650. 
An analysis of the Papehue colony on the basis of the statistical determinations 
(table 231) must be more complex, because the collections of two different years are 
involved, the first of which (1906) was taken in the lower valley, while that of 1907 
was secured from a more interior situation. The two color-classes of the first year 
do not differ greatly; their correspondents of the second series differ widely in 
absolute measure, but to insignificant degrees in proportionate measures; the single 
brown shell is very aberrant, and not in the directions from the average taken by 
the brown individuals of Aoua. Comparing the two annual series, it appears that 
the outer colony comprises larger shells, with apertures of lesser relative length. 
At several other points in the foregoing sections, when it was possible to compare 
collections taken at different distances from the coast in a single valley, the same 
