204. VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
Analyzed on the basis of the statistics (table 141), the lightest shells prove to 
be larger than the rest—a relation disclosed in previously described colonies. The 
banded shells are substantially the same as their plain relatives. 
The fecundity of the series (table 142) is such as to provide a large number 
of young for the consideration of heredity (table 142). As before, there is a 
dearth of banded young; yet among the adolescents, which represent an intermediate 
generation, this color-form was represented by a large percentage. The discrep- 
ancies observed are difficult to interpret. 
TasLe 142.—Partula otaheitana affinis. Paraura Valley. 
FECUNDITY. HEREDITY. 
No. of | Per cent} No. of 
gravid.| gravid. | eggs. 
No. of | Total | Average | Average 
Young,| Young, 
young. |contents.|for gravid.| for all. tort 
plain. |banded. 
Series. Records. 
planter 400 355 88.7 490 227 717 2.02 1.79 Adults: 
Banded... 112 95 84.8 137 51 188 1.98 1.68 Plaine ee) 2 227 
| Banded... 46 SS) 51 
450 87.8 627 278 905 2.01 1.76 
ANA coool] Til -T-+ 278 
Faatautia, Papetna, Uruural, AND FAoNE VALLEYS. 
The combined discussion of the affinis colonies existing in these four valleys 
does not imply that no discernible or significant differences are displayed, but only 
‘that the associations are sufficiently uniform to render separate treatment unneces- 
sary. By no means negligible is the lack of similarity in the absolute or relative 
abundance of this primary variety, for it signifies a real constitutional variation 
of the colonies, on a par with that displayed in the relative numbers of the two 
major color-classes or in the dimensions of the shells. 
The figures given earlier show that the plain and banded classes are numerically 
in the proportions of 3:1, 10:1, 4:1, and 7:1, respectively. The banded shells 
are all dubia in Faatautia (plate 29, fig. 52), while both types occur in the other 
valleys (plate 29, fig. 53, example from Papeiha). 
The statistics relating to the shells (table 143) show differences between colonies 
of contiguous areas, manifested sometimes in one character and at other times in 
another measure or relation; in general, a color-class agrees more with the other 
class of its own region than with the similar group of a neighboring area. The 
collective statistical descriptions are more valuable for a general summary treatment 
of affinis. Considerable variation in fecundity is observed (table 144), although 
the collections were secured in the same year within a period of three days. Natu- 
rally the figures for Faatautia are the least significant. 
The inheritance of the distinctive color-characters (table 145) seems to be quite 
consistent, if we disregard the small series from Faatautia. Each major class pro- 
duces its own kind, but some of its offspring belong to the other group. The rela- 
tive numbers in the adult and embryonic populations are closely similar in each of 
the three valleys yielding reliable data. It will be recalled that in certain earlier- 
described colonies (¢. g., that of Paraura) wide discrepancies were found; the sub- 
stantial agreement in these cases tends to eliminate the supposition that a constant 
error of observation has been made. 
