152 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
measures are much less (see table 90); the tooth appears as a trace in only one of 
the eight specimens. ‘The statistics of fecundity and of the heredity of ground- 
color are naturally few (table 90), but the latter are valuable as indicating that 
the two color-classes interbreed, or, at least, that they are not absolutely separated 
and independent. 
TaBLe 90.—Partula otaheitana rubescens, Tuauru Valley. 
STATISTICAL DESCRIPTION. 
Character. Class range. Mean value. Standard deviation. 
Shell #length) ‘mimi o shee oe ere ee A aC eo 18.25-20.25 19.5000 .1333 0.5590 .0942 
widthyemms ccs oan nae eee rere ates 10.15-11.15 10.5500+ .0884 .3708+ .0625 
proportions; pericent:/jcrecteileyn stciorsin o> #1 hey seueveheiel suis s 51.5 -56.5 54.0000= .4130 1.7320+ .2920 
ANE AANy T1VINOG5Gag0060000000000000000000000000 9.1 -10.1 9.7000 .0754 .3162= .0533 
Widtbiomm ek Gist ierxctonicncikek eee eric 6.9 — 7.5 7.2250 .0473 .1984+ .0334 
proportions perscentinnyaaoeieirereeereticr: 71.5 -78.5 75.1250 .4608 1.9324 .3258 
Length aperture + length shell, proportions, per cent....... 47.5 —51.5 49.3750 .4034 1.6918+ .2852 
Moothindexsrrereoeee ee BAO ABO ORO DR DUO ODA RG nOCGS 1.1250+ .0789 . 3318+ .0558 
Frecunpity (6 Recorps). HEREDITY. 
Young,| Young, Total 
yellow.| red. i 
Gravidin: eee see. See ee Se ae 4 Adults: 
Gravidpericentiemeeiec eerie tere G6S6r I Wellow.cr..ciereoeierecrteree niet 
le oaponoooando od oMUdoGUOe CUDSOOOU DUO MAL) RAE aR hem he pe 2 oS > 
M@linigoooon0 comooD ano dGbada000 000000 Jive ||) Mehotalty. eikaeneterttacerraelerraeeeeriee 
Averagelforctravidemereicretccctercciereietsieteneiere 2.25 
Average:foriall ic cnccose;cjqstepercrete cutecststsueme ere is 
The adult specimens from Ahonu amount to 146, or 49.4 per cent of the whole 
full-grown otaheitana population. They are readily separated into the two prin- 
cipal color-classes, of which the yellow predominates. Of the examples figured 
belonging to the yellow class (plate 26, figs. 54 to 57), one illustrates the result of 
decortication (fig. 54); in the case of the red class (plate 26, figs. 58 to 63), decorti- 
cation changes the color to a pinkish tinge (plate 26, fig. 58). The examples show 
at a glance that the shells of this colony are larger than those of Tuauru, and also 
that the second color-type displays a clearer red. 
The colonial statistics (table 91) are sufficient to give a basis for a full compari- 
son of the two classes. It appears that the yellow shells are larger than the red ones, 
to a significant degree in shell length, aperture length, and perhaps in the width of 
the aperture; there are also significant differences in the proportions of the shell as 
a whole and of the aperture. In brief, the red shells, in general, are smaller and 
more closely coiled—a fact to be borne in mind when similar classes of the succeeding 
valleys are compared in detail. 
The pillar tooth is remarkably developed in this colony; only in Papenoo is it 
exceeded (table 92). 
