PARTULA. 



121 



The snails are probably nocturnal, for they were almost never found 

 crawlino- during the day. With five exceptions they were all found upon 

 the under sides of the leaves and stems of the plants they affect. They 

 show a very decided preference for certain plants, and almost all of them 

 were discovered upon the wild plantain and Caladium. In Hamuta valley, 

 however, the}" were quite abundant upon Dractena; and in Vaihiria the 

 great majority of them were found upon the Turmeric. About lialf a dozen 

 snails were found upon the stems of Guava (Psidium guaiava), " Purau " 

 (Paritium tiliaceum), and upon various species of ferns. 



It was my habit to spend the greater part of a day in each of the valleys 

 and to take every snail which was seen. 



As is well known, these snails are hermaphroditic and viviparous, and 

 bring forth their young in an advanced state of development ; and in order 

 to facilitate the study of the relationships between the various forms, the 

 young were dissected out from every adult containing them. The follovv'- 

 ing table will show the number of snails cajitured in each valley, the 

 number of adults which contained young snails, and the number of young 

 which were dissected out from them. It will also show what might be 

 termed the " ratio of fecundity," or the number of young for adult con- 

 tainiu"- them. 



We see from the above table that the snails differ both in abundance, 

 and in their fecundity in the various valleys. 



Certain general statements may, however, be made concerning the Par- 

 tulas of all six valleys. For example, the young of dextral or sinistral snails 



1 These snails were collected in about two hours instead of in six hours, as in other cases. 



