CHAPTER IV. 
PARTULA CLARA Pease. 
GENERAL CONSIDERATIONS. 
Like hyalina, Partula clara is a well-separated species with a virtually unclouded 
taxonomic history. It occurs only in Tahiti; in its restriction to a single island it 
agrees with most of the other species of the genus, and stands in sharp contrast to 
hyalina. In addition to variations in size and shape, in different localities it also 
exhibits color variations of a striking nature. In brief, it presents many features 
of distribution that are similar to those offered by hyalina, while it adds to these 
certain other peculiarities of high significance. 
Pease described clara in 1864 as follows: 
“P(artula) T(esta) ovata, subelongata, tenui, subpellucida, vix nitida, anguste umbili- 
cata; anfr. [V., tenuiter et regulariter transversim striatis plano-convexis; apertura ovata, 
subobliqua, edentata, labro plane incrassato; flavide cornea vel pallide castanea, strigis 
longitudinaliter variegata. Long. 16, diam. 10 mill. Var: Linea unica, vel lineis duabus 
tribusve cingulata.” 
Carpenter, in commenting on the above description by Pease, says that “clara 
seems to be a variety of the form returned by Mr. Cuming as P. hyalina Brod.” 
and a similar confusion exists in the case of some of the specimens at the Smithsonian 
Institution, as noted also by E. A. Smith. With these exceptions, clara has always 
been recognized as a clear species, although an ally of hyalina. Among the char- 
acteristics that indicate this proximity are the somewhat thin and transparent 
texture of the shell, its delicate and almost microscopic surface sculpturing, the 
invariable dextral coil, the total absence of a pillar tooth, except in the shells of 
one valley, and the obliquity of the aperture. 
By far the most important statement in the literature is Garrett’s paragraph 
referring to clara. He says this is a “rare species confined to the upper portions of 
the valleys in the southwest part of Tahiti. Like P. annectens, of Huahine, and 
P. turgida of Raiatea, it is gradually becoming extinct.” (Italics mine.) No doubt 
the species was rare at the time Garrett made his accurate and painstaking sur- 
veys, but it is equally clear from my own studies that it is far from being rare or 
infrequent at present; though it does not occur in all parts of the island, like hyalina, 
it exceeds the latter species in total numbers. Furthermore, the territory nozw 
occupied includes the eastern quadrant and Taiarapu, all of the southern quadrant, 
and the western sector as far north as Punaruu. The changes demonstrated by the 
comparison of the present situation with the state of affairs described by Garrett are 
clearly of the utmost importance for the present study of distribution and specific 
modification. 
57 
