Partula protracta, new species
Figure 3D
Shell dextral, moderately elongated, and solid. Whorls five and onehalf.
Spire prolonged, with flatly convex whorls and somewhat obtuse
apex; the last whorl is not tumose. Suture impressed only on the terminal
third of the body whorl. Umbilicus compressed. Surface marked
with lines of incremental growth that are more prominent towards the
outer peristome. The columella is vertical, broad at its base, and shouldered;
the lower notch of related forms is represented by a small and
shallow indentation. Parietal callus thin and lustrous; its arched border
1956 CRAMPTON: LAND SNAILS 13
is thickened at its junctions with the termini of the peristome. Parietal
tooth small.
Aperture slightly oblique. Peristome well developed and thickened,
somewhat declivous within, and narrowed towards its outer insertion so
as to render the aperture subauriculate. A low but definite carina traverses
the entire lip near its outer border.
The color is uniform pale whitish buff. The peristome is lightly tinged
with pale buff. The apex is devoid of deeper pigmentation.
MEASUREMENTS OF HOLOTYPE: Shell length, 19.8 mm.; shell width,
11.8 mm.; shell proportions, 59.6 per cent; aperture length, 10.3 mm.;
aperture width, 8.4 mm.; aperture proportions, 8.1 per cent; proportions
of aperture length to shell length, 81.5 per cent.
HABITAT: Huaru Valley, Raiatea, Society Islands. Arboreal.
In 1908 a single half-grown animal was found in Huaru Valley (fig. 1)
the shell of which differed markedly from shells of the other species of
its valley or elsewhere. Fortunately a full-grown and perfect individual
of the same kind was discovered in 1909 when a second search was
made in the higher portion of the valley. The general constitution of the
adult specimen is sufficiently like that of the unquestionable members of
the "robusta group" to justify its assignment to that section of the
Partula fauna of Raiatea.
In contrast with its affiliated forms, the shell of this species is longer
and more slender. The aperture is relatively smaller, and the proportion
of its main axis to that of the whole shell is distinctly less. In addition,
the apex is more obtuse, the umbilicus is more narrowly rimate, and the
axis of the columella is vertical and not inclined. The outer terminus of
the peristome meets the body whorl at a right angle. Finally, the color
is much lighter than in any of the other members of the group. These
individual distinctions are sufficient to separate this type from all the
related species that exist in areas either to the north or to the south of
Huaru Valley.
digitallibrary.amnh.org/dspace/bitstream/2246/4738/1/N1761.pdfPDF file found by noisi
