'Top-shells and Fheasant-shell 209 



with white, pink, or purple. There are but 3 

 whorls, and the last of these is equal to at least 

 two-thirds of the whole slielL The operculum is 

 half-moon shaped, corresponding with the shape 

 of the mouth, shelly and solid, coloured yellow or 

 orange, and spirally grooved ; beneath there is a 

 sickle-shaped projection which serves to keep it in 

 position when it closes the shell. The animal — • 

 which is yellowish grey spotted with black, and 

 has a black head — shows its relationship to the 

 Top-shells by its possession of a strong snout. It 

 has long tentacles, almost transparent, streaked, with 

 black ; and large black eyes on short foot-stalks. 

 It is found in clear gravel-bottomed rivers, spar- 

 ingly at the mouth where the water is brackish ; 

 more frequently in the upper reaches. The globular 

 egg-capsules are usually deposited on the shell 

 of another individual, and a singular provision 

 is made for the welfare of the young — though at 

 seemingly great expense. Each capsule contains 

 50 or 60 eggs, but only one embryo is permitted 

 to develop, and this sets to work to demolish its 

 brothers and sisters. 



