I92I.] 



Maniptir Molluscs. 



547 



The outline is ovate and the external surface broadh' concave 

 with the concentric ridges poorly developed. The internal surface 



B. 



C 



Fig. 4. — Shells of Viinpara mieyochaetophora. 



A. — Youno- shell. B. — Shell of voung adult. 



C— Old shell. 



is convex as a whole. The muscular scar is poorly developed and 

 only a little darker than the rest of the operculum. It covers a 

 considerable area as a minutely granular thickening. 



