286 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
TaBLeE 242.—Partula otaheitana crassa. Collective description. 2,/20 sinistral shells. 
Mean value. Standard deviation. 
Character. ———S SS 
Combined Average of Combined Average of 
series. valley types. series. valley types. 
Shell Jengthimmjsaociotor hancock OO ELC EEL EEE 17.2787 .0117 17.3231 0.9081 = .0083 0.8441 
WiIdthyim Ms recive eee TAR TerOcicr arenes 10.0069 = .0066 10.0367 .5105= .0046 4474 
OVO) NOVAS) Jorere GEM no 0000000000000000000000 57 .8423+ .0324 57.8527 2.5101 .0229 2.3640 
Apercureviensthsmmeeeereece eee eee eee 9.1292 .0067 9.1517 .5157=+ .0047 .4670 
Wid thm te sets ea oe ee Pe 6.8899 .0051 6.9124 .3931+ .0036 .3693 
DLOPOLLIONS BpClaCen Uae eit eee iterate 75.3860 .0379 75.4455 2.9342 .0268 2.6078 
Length aperture + length shell, proportions, percent. ..| 52.7566+ .0260 52.7531 2.0096=+ .0184 1.8776 
mMoothpindex asa k. yes Be ace cee eae 2.5122 .0120 2.6279 .9438=+ .0085 .8061 
IN = 2,790. 
PARTULA OTAHEITANA LIGNARIA Pease. 
GENERAL CONSIDERATIONS. 
The primary variety now to be described occupies the single valley of Tipaerui, 
which is located between Taapuna in the west quadrant and Fautaua Valley in the 
northern sector, and is the last connecting topographical element in the circuit of 
the island. The variety in question was described by Pease as a separate species, 
but its alliance with otaheitana was specifically mentioned. Although it has been 
confused with Partula otaheitana affinis it is really as distinct in morphological 
respects as its locality is disconnected geographically and topographically. 
Nearly 1,000 adult snails (959) were taken during the several annual periods 
of field-work, together with over 400 adolescent individuals; 377 advanced embry- 
onic snails and 372 eggs were dissected out of the gravid adults. This material 
affords an opportunity for an analysis that is particularly significant and valuable on 
account of the restricted habitat of /ignaria and because of its sharply marked 
differences from the nearest colonies on either side. 
The original description of Pease (P. Z. S. 1864, p. 671) is quoted in full: 
“P(artula) t(esta) ovata, solidiuscula, dextrorsa, anguste umbilicata, sub lente minu- 
tissime transversim striata, irregulariter longitudinaliter striata; anfr. V. plano-convexis, 
sutura impressa; apertura rotunda-ovata, edentata, labro rotundatim incrassato; casteneo- 
fusca irregulariter longitudinaliter strigata, interdum omnino rufo-fusca. Long. 18, diam. 
to mill. 
“Var Fascia unica nigro-fusca cingulata, seu omnino flavide fusca. 
“The tubercular tooth on the wall of the aperture is seldom wanting, and there is 
generally a slight angle in the outer lip at its junction with the body whorl. It is allied to 
P. tahitiana [otaheitana]; the latter, however, is more elongate, and both dextral and 
sinistral; it is more varied in its colors, and the lip is usually rosaceous.” 
Garrett’s important statements (p. 48) are as follows: 
“Tn a valley about two miles west of Fantana [Fautaua], there exists in abundance 
the variety (?) lignaria Pease, which, although described as dextral, is nevertheless very 
frequently sinistral. ‘Though not attaining quite so large a size as the Fautaua shells, it 
differs none in shape, but is usually darker colored and more strigated, as well as exhibiting 
