94 VARIATION, DISTRIBUTION, AND EVOLUTION OF THE GENUS PARTULA. 
in a more interior position in the brood-pouch. Only 10 such instances were dis- 
covered in the 2,046 gravid adults, while in radiolata there were 23 among 1,313 
bearing individuals. The data for the gibba instances are given in table 46. 
TABLE 46.—Partula gibba, Guam. Aberrations in the order 
of embryonic contents. 
Locality. Number of | Embryonic contents. 
instances. 
‘OlvQSUCs a. ina ae 1 e Y¥ 
2 e Yee 
1 Vi. Cie Var ease e 
Asados vac pc Steen ak 1 e Ye 
Barrigarday... se ae 2 e Ye 
UIKUGG Secs werent ete 1 e Yeee 
Macajna second........ 1 CX ere 
ARIQURC oot ace as 1 Vv CPt yee 
The number of embryonic items ranges from none to 8 at the most, and the full 
statistics in this connection are duly recorded in table 47. 
TABLE 47.—Partula gibba, Guam. Recorded adults and their embryonic contents. 
Number of young. 
506 
621 
790 
361 
96}3,721 eggs. 
2,384 records. 
2,332 young 
Embryonic contents. 
Summary. 
Number of adults 
(=2) 384) 

We now come to the problems of heredity which are the same as in the case 
of radiolata; but the late development of the distinctive color-phases of gibba renders 
the material less demonstrative than in the other species. One thing is sure, how- 
ever, namely, that the young snails dissected from the adults are dextral in coil 
without a single exception; the same is true for all of the adolescents as well as for 
the adults, and hence there is no evidence that sporadic sinistral mutations occur in 
gibba as they do in some species of the Society Islands. 
