220 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
from the other primary varieties, they constitute a division with a status equivalent 
to that of the latter. However, in order to avoid the establishment of too many 
taxonomic terms, the group as a whole will be called simply the sinistral series of the 
south and west, while its three components will be specified by their original names, 
P. o. sinistrorsa, P. 0. sinistralis, and P. 0. crassa. They will be treated in this order, 
as so many subspecies. 
Each of these divisions, in its turn, 1s differentiated into subordinate parts, on 
the basis of colonial characters that are sometimes entirely unique for a given valley, 
and sometimes are shared by the associations of a short series of adjoining localities. 
Hence any one of these three divisions is quite as complex as P. o. affinis itself, or 
another primary variety. 
Obviously, then, we are confronted with an extremely heterogeneous otaheitana 
population, and with attendant difficulties in the way of analyzing and describing it. 
But the difficulties may be avoided in greater part, and the situation may be more 
clearly comprehended, if it be borne in mind that sintstrorsa, sintstralis, and crassa 
are three parts of P. otaheitana that resemble one another more than any one of 
them resembles a contrasted primary variety. 
Garrett’s statements regarding this series are more than ever important, in 
view of the intrinsic interest of the snails themselves as well as on account of the 
geographical facts. He says (pp. 49, 50): 
““Pease’s sinistrorsa is confined to the south coast of Tahiti proper, where it exists in 
the greatest profusion in all the valleys and lowland forests for a distance of ten or twelve 
miles. In the valley which is the limit of the range of the dextral affinis [Apirimaue, then 
as now] I took several specimens of the sinistral sinistrorsa. The latter is invariably 
reversed, dentate or edentate, fulvous with three more or less diffused reddish chestnut 
bands. Reeve figures the same shell on Plate 3, figure 13a, as Otaheitana. Bandless vari- 
eties are frequent, and vary from straw yellow to fulvous or light chestnut, frequently 
strigated and the lip white. The latter varieties differ none from the true Otaheitana of 
Rantana |Rauiamal, “ * © 
“Tt is worthy of remark that in that part of the district of Papieri [Papeari] occupied 
by sinistrorsa is also the headquarters of the terrestrial P. producta, a dextral species which 
is always edentate, and exhibits the fasciation of the former. 
“After passing to the westward of the range of the typical sinistrorsa, which presents 
the same features for a distance of ten or twelve miles, it suddenly exhibits a tendency to a 
change in its becoming more stunted, more solid, always dentated, and the bands, one to 
three, are sharply defined on a pale ground. It is the sinistralis of Pease, ms., and occupies 
two valleys. 
“Tn the next large valley, called Faahuaite [Orofere], on the southeast coast, we find 
‘Pease’s’ crassa (ms.), which is also a sinistral shell, always dentated, solid, more tightly 
coiled than sinistrorsa and the body whorl is more flattened. It is rarely marked by a 
single narrow submedian chestnut band. In the same valley, but more inland, occurs a 
smaller form, which is, I suppose, the P. brevicula Pse., ms. 
“The following valley, named Punaavia [Punaruul], is the metropolis of the beautiful 
P. nodosa, which also exhibits three bands. Far above the restricted range of the latter, 
where the valley turns towards the head of Fantana [Fautaua] the home of the typical 
Otaheitana, I took a few examples of a Partula, similar to, but larger than, crassa. The 
next valley in the habitat of lignaria.” 
