188 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
distinct in morphological characters and so separated geographically that a secon- 
dary varietal term is employed for the purpose of accurate and concise definition. 
This procedure implies that such a group stands more apart genetically than do the 
several colonies that are not thus distinguished. 
TasBLe 119.—Partula otaheitana affinis. Census of the collections. 
Dextral. Sinistral. Per cent of dextral.|Per cent of sinistral. 
Series and valley. 
Banded.| Plain. | Banded.| Plain. | Banded.| Plain. Banded. 
Northern: 
Faaripoo 
Papenoo 
erythrea: 
w 
a 
Paraura 
Faatautia 
Papeiha 
Utuufai 
COoPORNARE 
w 
= 
Hototunu 
Vaiaaia 
1Bicolored, not striped. 
A brief résumé of the general situation will aid in comprehending the detailed 
analysis of the several colonies of this variety. In the northernmost part of the 
range the shells are typical and require no special qualifying term, although the 
banded specimens differ somewhat from those found elsewhere. The colonies of 
this area, which extends from Tuauru to Papenoo Valleys inclusive, are called 
merely the “northern series.” A unique association is found in the next valley, 
Farapa, and in that restricted area only; it is named erythrea on account of the red- 
dish color that is displayed by the majority of the shells. From Faarumai to Faone, 
that is, throughout the rest of the eastern sector, the shells are much like those of 
the northern series, but among them are representatives of the three-banded color- 
type named dubia by Pease and regarded by Pilsbry as a subspecies of otaheitana; 
it is really only a color-form, to be distinguished orthographically as dubia; in 
