PARTULA. 129 



Pariula hjalina, Figs. 1, 2. Partula nbmtrorsa Pease, Figs. 11-13. 

 Vaihiria Valley. 



V.ailiiria valley is situated on the south side of the Island, about nineteen 

 miles from Maruapoo, from which it is separated by about thirty ridges. 

 There appear to be but two species of Partula in this valley, one of which is 

 P. hyalina, represented in Figs. 1 and 2. The other species, P. sinistrorsa, 

 represented in Figs. 11-13, constitutes 98 per cent of the snail fauna of the 

 valley. These snails are very variable in color, and were it not for the fact 

 that they all ^ give light yellow-white colored young they might readily be 

 mistaken for several distinct species. Sixty-one per cent of the snails of 

 this species belong to the type illustrated in Figs. 11 and 12, where the 

 surface of the shell is smooth and polished and the ground color is of a light 

 horny-yellow. Two broad whorl-bands of darker color traverse the body- 

 whorl, and usually extend about the distance of another whorl up the spire 

 of the shell. In about 95 per cent of these shells the whorl-stripes are of 

 a rich dark-brown, as in Fig. 11, while in about 5 per cent they are faint 

 in color, as in Fig. 12, or absent. 



In about 8 per cent of the snails belonging to the predominant species 

 of Vaihiria valley the ground-color is of a light horny-yellow, very similar 

 to the color of Fig. 3, while in about 16 per cent the ground-color is 

 of a light horny-brown, streaked longitudinally with darker brown, giving 

 very much the appearance of Fig. 5. Again, in about 10 per cent the 

 shell is of a uniform rich dark-brown, similar in color to Fig. 4. Finally, 

 in about 3 per cent of the snails the shell is parti-colored, the body-whorl 

 being light horny-yellow, while the spire is rich brown, as in Fig. 13. 



The snails of Vaihiria valley may be distinguished from those of similar 

 color in Tipajrui, Fautaua, Hamuta, and Piroe valleys by the following char- 

 acters: In Vaihiria valley the snails lack a tooth upon the wall of the 

 aperture, and the lip is relatively thin and fragile. The shell is also more 

 constricted at the suture than is the case in the snails of the valleys near 



* A single light-brown adult gave one light-brown young; all of the olhurs gavt: light yellow-wliite col- 

 ored young ones. 



