130 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
heitana as the relatively unchanged descendant of an old stock of great intrinsic 
complexity, formerly widespread over Tahiti, and one whose descendants in other 
valleys have dropped out one or more of the original qualities which have been 
retained by some of the varying members of the Fautaua association. 
PARTULA OTAHEITANA AMABILIS Pfeiffer. 
GENERAL STATEMENT. 
Beginning with the small valley of Hamuta, the immediate eastward neighbor 
of Fautaua, the valleys as far as Tuauru are inhabited by representatives of Partula 
otaheitana that are sufficiently distinctive to be grouped together as a primary 
variety; this is called amabilis because certain characteristic shells were described 
by Pfeiffer as a separate species under that name. ‘The variety ranges through 
Hamuta, Pirai, Pohaitara, and Ururoa valleys, giving place beyond to the invari- 
ably sinistral rubescens and the predominantly dextral affinis. 
Pfeiffer’s original description of amabilis is as follows: 
“Shell sinistral, subperforate, ovate-turrite, rather solid, striatulate, glossy, citrine, 
the acute apex reddish, suture white-edged. Whorls five, the upper flat, the rest convex, 
the last shorter than the spire. Columella nearly simple, slightly plicate. Aperture 
oblong-semi-oval. Peristome somewhat thickened, white, expanded and reflexed, the 
columella margin wide, flat, spreading. Length 23; fine II; aperture inside 9} to 10 mm. 
long, 5 wide. A variety is somewhat smaller, ornamented with wide blackish-chestnut 
bands, the peristome livid brown.” 
Two items of the above account are amazingly incorrect. P.0. amabilis is not 
as long as 23 mm. in a single shell out of more than 3,000 in my collections. Only 
a few examples of P. 0. rubescens, at the height of its development in Oopu Valley, 
far to the southeast, exceed 23 mm.; an equally small number of the P. 0. sintstrorsa 
series, again far to the southeast, are as long as 23 mm. _ I suspect that the figure 
given by Pfeiffer is incorrect to the extent of 5 mm., 23 being read for 18 on the 
scale. In the second place, no specimens of amabilis occur with “wide blackish- 
chestnut bands’; such shells are members of the sinistrorsa series. Pfeiffer’s error 
in this respect is perpetuated in practically all the large conchological collections of 
the world, excepting only those which were made and labeled by Garrett, who was 
well acquainted with amabilis and other varieties from his own experience. 
Garrett’s monograph gives the following description of the distribution of 
amabilis (p. 48): 
“To the eastward between Fautaua and Papenoo Valley, a distance of about eight 
miles, there are three valleys, all inhabited by Pfeiffer’s amabilis, a sinistral form that 
has not a single feature to distinguish it from some of the larger turreted Fautaua shells. 
In the first valley [Hamuta], Pfeiffer’s species, though not abundant, were very fine 
specimens. The next valley, known as Pirai (the metropolis of the small dextral P. jilosa, 
which occupies the lower part of the valley) is, in the upper part, which trends toward the 
headquarters of otaheitana, inhabited by the sinistral amabilis. A few immature examples 
were found which were banded like Lignaria. ‘The only dextral Partule taken in the two 
