264 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
The data of heredity (table 216) give certain interesting results. As observed, 
the banded pattern is displayed by very few of the young, in comparison with its 
prevalence among the adults; as before, it is something that seems to develop late. 
The most notable point is the chiasma of the coil in inheritance, in such a way as to 
make the relative numbers almost the same in both the offspring and parental 
generations! 
TaBLe 216.—Partula otaheitana sinistralis. Tiamao Valley. 
Herepity, Fur, Data. 
Young, sin. Young, dex. 
SSS SS |) SSS =| Poti. 
Plain. | Banded.| Plain. | Banded. 
Adults: 
Sins splain=eeeeee id sie 3 3 6 
banded..... 36 65 2 19 122 
iDexsyplains=eeer 1 oe 7 ye 8 
banded.... 22 9 51 48 130 
otal iasswecoe 59 74 63 70 266 
Summary. Herepiry oF Coton PaTrern. Summary. HEREDITY OF SPIRALITY. 
Young, Young, 
plain, banded, Total. neue venae Total. 
sin. +dex.| sin. +-dex. 3 xtra 
Adults: Adults: 
Plain, sin. and dex... 11 3 14 Sinistral... 101 27 128 
Banded, sin. and dex. 111 141 252 Dextral... 32 106 138 
sRotaleesmcn- cover: 122 144 266 shotaleeeer 133 133 266 
VAIPUARIL VALLEY. 
Vaipuarii Valley is listed as the southernmost element of the western series 
rather than the westernmost member of the localities situated in the southern 
quadrant, because it lies beyond the main mountain ridge running upwards from 
Maraa, at the southwest corner of the island, to culminate in Mount Mahutaa, 
nearly 5,000 feet high. It has been stated that the area between Temarua and 
Orofere Valleys is a compact land-sector in which lie most of the areas inhabited by 
sinistralis. On the further slopes of the main ridge forming the spine of this sector 
are many valleys, mainly of secondary or tertiary size, among which only Vaipuaril 
is occupied by sinistralis; in the others crassa occurs. 
Less than a mile intervenes between the mouth of Tiamao and that of Vaipuaril, 
and a still smaller distance separates the inward parts of the two valleys as they 
converge in the course of their upward trend. Yet the s:nistralis colony of Vaipuarii 
is decidedly unlike that of Tiamao or of any eastward area. No dextral individuals 
were found in a series of 180 adults, 94 adolescents, and 119 young; furthermore, 
the shells attain a much larger size than in the neighboring valleys to the east. 
About 22 per cent (exactly 38) are unstriped phea shells, grading from confluens 
to striata in the distinctness of the cross-markings (plate 32, figs. 58 to 61). The 
