130 EXPEDITION OF THE "ALBATROSS," 1899-1900. 



Papeete. Moreover, no matter what the color of the adult shell may be in 

 Vaihiria, the young is light yellow, almost white. 



All of the snails of the types represented by Figs. 11-13 are sinistral, as 

 are also their young. Six snails of a imiform dark-brown color were 

 found, and of these five were sinistral and one dextral. Among these, only 

 one adult, a sinistral one, gave a single sinistral young. 



Five light horny-yellow snails of uniform plain color were found, and all 

 of these were dextral. Among them two adults gave rise to four dextral 

 young. It is possible that these light-colored dextral snails may be con- 

 sidered specifically distinct from their darker associates, but as they give 

 rise to young of the same color and general appearance as do the other 

 snails of the valley, it seems probable that no specific distinction can be 

 drawn. 



Ten snails of a light horny-brown ground-color, streaked longitudinally 

 with darker brown, were found. All were sinistral, and four of them gave 

 six sinistral young. 



Altogether, 90 per cent of the snails of Vaihiria valley are sinistral, as 

 are also 90 per cent of the young dissected from them. 



General Conclusions. 



In Tahiti five species of Partula were found in the six valleys of Pirse, 

 Hamuta, Fautaua, Tipajrui, Maruapoo, and Vaihiria. 



One species (P. hyalina Broderip), represented in Figs. 1 and 2, is rare 

 everywhere, and yet it is found in all of the valleys. This is the only 

 snail that is universally distributed. Another (P. otaheitana), shown in 

 Figs. 3-8, is predominant in Pira3, Hamuta, Fautaua, and Tipserui, but 

 is not found in the other valleys. The three other species are restricted 

 each to a single valley. For example, the species shown in Figs. 9, 10 

 (P. filosa) is found only in Piraj vallej^, while the forms illustrated in 

 Figs. 11-13 (P. sinistrorsa), and 14, 15 (P. nodosa var. sinistralis) are 

 found, the former in Vaihiria and the latter in Maruapoo valley. 



Partula hyalina, represented in Figs. 1 and 2, is very stable in all 

 of the valleys, and gives rise to no varieties. All of the other species, how- 

 ever, are remarkably variable, and give rise to numerous color-sports. 



