PARTULA NODOSA. 103 
from another part of the colony’s range. From the figures, therefore, it is plain 
that the banded examples greatly outnumber the plain shells in the remoter areas, 
for in the proximate region they are in the minority, as shown by the data for 1907. 
This is the reverse of the relation between the two classes as they exist in Maruapoo. 
Contrasting the two series on the basis of the statistical determinations (table 
48) it appears that the animals of the lower part of the colony are somewhat smaller 
in absolute measures, while they are narrower in the proportions of the whole shell 
and of its aperture; in the proportion of aperture length to shell length, its con- 
stituents exhibit a higher value. Furthermore, the two classes differ markedly in 
certain characters, in each of the annual series. Nearly all of the shells bear a 
pillar tooth (table 49), only 6 out of 210 lacking this feature. In fecundity (table 
49) low reproductive rates are indicated for both years. 
Heredity of the class character of color is sensibly strict (table 49), especially 
in the case of banded forms, although allowance must be made for the late appear- 
ance of the bands in embryonic development. Scant as the data may be, they 
prove positively that the two classes are not genetically distinct here, any more than 
in other valleys. 
Partula nodosa intermedia var. nov.—Aoua Valley. 
This gorge is slightly larger than Papehue, and is the last of the lesser elements 
in the southward range of nodosa. More than 500 specimens of this species were 
secured here, of which 396 were adult and 115 were partly grown. All were dextral 
with the exception of a single immature banded example. As awhole, the colony stands 
near the original stock, which is now represented by the Taapuna and Punaruu 
shells, as all four color-classes of the northern section are clearly distinguishable. 
Although the intrinsic characters are under consideration here, it is well to point 
out that the Aoua colony seems to be the direct derivative of var. composita, and 
that it has secondarily given off the colonies of Orofere to the south and Papehue 
to the north; from the latter, which still resembles the Aoua group on the whole, 
the Atehi variety, exigua, seems to have been produced at a still later period. In 
brief, the Aoua colony is the typical intermedia. 
The numbers assignable to the several color-classes are as follows: 
¢ Number 
Class.| Figures and plates. OGIA. Percent. 
I Figs. 25, 26, plate 24 2 0.5 
II Figs. 27 to 30, plate 24 321 81.0 
Ill Fig. 31, plate 24 23 5.8 
IV_ | Figs. 32 to 34, plate 24 50 12.6 
396 99.9 
Very light shells like pallidior of var. composita reappear, although in small 
numbers. Class III (concrescens) is well represented. The shells of Class IV show 
a weakly marked white sutural zone, if it appears at all. 
