150 



PROCEEDINGS OF THE ACADEMY OF 



[Feb., 



accompanying plot, fig. 10, in which all forms with a width of 39 mm. or 

 over (with the exception of one, 39 x 23 mm.) belong to group A. 



The shells in this colony were plentiful, and both in February and 

 March and also in May living forms were collected in abundance. In 

 March the young were perhaps somewhat more plentiful, but a good 

 series were collected in May, when the suites above described were 

 taken. The young ranged from 3 whorls to 4^ whorls in diameter, 

 they move actively about above the surface of leaves and probably 



Fig. 10.— Bloomfield. 



most of the migration occurs between a size of 2\ whorls and of 4 

 whorls. At about 4 whorls the adult characters begin to appear, and 

 the umbilicus to contract as the size of the opening of the shell expands, 

 but the development of the shell will be given in another place. 



Pleurodonte acuta goniasmos A. D. B. Plate XI, figs. 1-3, 5. 



At the Kendal Road colony, 3h miles from Mandeville. 



Shell varying from rather high in the spire to as flat as the Somerset 

 normal forms, consisting of 5^ to 5^ whorls; only 2 out of the 18 

 examples (Plate XI, figs. 3 and 5) had a depressed spire, so that the 

 index fell below .50 (.455 and .487), but in 5 others it was below .53 

 (.51, .512, .512, .524, .525). On the other hand, 4 had a much elevated 

 spire, above .60 (.607, .61, .62, .62). The average index for the whole 

 series was .55. They include shells that range in index below the 

 lowest from Benmore woods, and some are also nearly as high in index 

 as the highest from this colony. The outline of the spire runs from 

 nearly linear to somewhat convex, but all show a slight excavation 

 above the periphery on the last whorl and the angle is rather pro- 

 nounced, one oi- two have this angle at the periphery much rounded. 



