PARTULA OTAHEITANA. 219 
TaBLe 160.—Partula otaheitana affinis. Summary description of dextral individuals. 
al | 
Mean value. Standard deviation. 
CERES Combined Average of Combined Average of 
series. valley types. series. valley types. 
Shell Plengthyem mvryyecrevireter = sarsievorsi te ietehes<taeranske carers ws 16.6187 .0092 16.4690 0.9770 .0065 0.7394 
Wi Ch spin Mr terewer sper cin cise vsheray cue tences eraveersvtie mw arerere 9.7068 .0049 9.6431 - 5236+ .0035 . 3902 
PLOPOLtIONS Bp aCUaemce ne elon ie oe 58.7047 .0209 58.4948 2.2150+ .0148 2.0545 
Aipertureplengthspmminsecrepsieicistcieielrsicachelvereverercictereiers 8.8076 .0052 8.6726 .5562+ .0037 -4172 
WIG EDS nm y. atsce errors. s eauatelere ssevareoteveverya acer 6.7488 .0042 6.5987 .4492 + .0030 . 3099 
KNOT, Th Gbocoocuccccc00s 0000000000 76.5190 .0261 75.9038 2.7678 .0185 2.3266 
Length aperture + length shell, proportions, p.ct...... 52.8743 .0175 52.5387 1.8584 .0124 1.6384 
PROOtH BING EX deyaisiaycisteyetoveretefe eesie) casera nieteors sate ® Susreeues 2.3125 .0071 2.2290 . 7260+ .0050 .7726 
1Number is 5,114, for all characters excepting the tooth, for which the number is 4,755. 
PARTULA OTAHEITANA SINISTRORSA Pease. 
GENERAL DESCRIPTION. 
Each of the primary varieties hitherto distinguished and described exhibits 
some degree of internal differentiation, but none displays the remarkable com- 
plexity of the triple series whose first section is now to be taken up, the series which, 
for reasons that will appear, must be designated as the sinistrorsa-sinistralis-crassa 
series. In the valleys located in the southern and western parts of Taiarapu and 
Tahiti nui the snails belonging to P. otaheitana differ from other primary forms and 
agree collectively in certain distinctive attributes. They are sinistral in coil, 
although here and there dextral individuals occur singly, or at times in considerable 
numbers. They display ground-colors of various shades of brown; the rich yellow 
and red of rubescens are lacking, save in certain very sharply localized associations 
in the western sector. In pattern they are of two general kinds, namely, banded 
and unbanded. Great variability in size occurs, for some shells are as small as 
affinis, while others are as large as the biggest rubescens; the shape also varies from 
stout to slender. The tooth is highly variable, some colonies possessing it in large 
degree, while others are devoid of it. 
Taken as a whole, this southern and western series of associations constitutes 
a primary division of Partula otaheitana in the sense that its constituents are collec- 
tively distinguishable from P. 0. rubescens, P. 0. affinis, etc., while they possess the 
basic characteristics of the species otaheitana. Yet its differentiation is such that 
three main sections can be readily recognized that differ znter se, it is true, but their 
differences are less than those which separate primary varieties from one another. 
The characteristic examples of these three sections, like those of the primary 
varieties already discussed, were first described and named as distinct species, 
namely, P. sinistrorsa, P. sinistralis, and P. crassa. ‘Their territories adjoin in 
geographical order from east to west and north, without overlapping, although 
P. o. affinis occurs in some valleys that are occupied by sinistrorsa. Garrett and 
others have recognized the otaheitana nature of these forms and have subordinated 
them to the same rank as rubescens, etc. But in so far as they collectively differ 
