The Top Shells and Dolphin Shells 



M. helicina, with thinner, more bulging shell, is found on 

 northern coast, feeding on the green Laminaria leaves. Its shell 

 is very small, about J- inch in two dimensions, distinguished 

 by its yellowish or olivaceous colour and iridescent, metallic 

 lustre. 



Habitat. — Maine, Alaska and northern Europe. 



THE DOLPHIN SHELLS 

 Genus DELPHINULA, Lam. 



Shell of a flattened top shape, solid, heavy, with large round 

 aperture and deep umbilicus; body whorl turns downward, nearly 

 free from the one next to it; all whorls keeled and spinose or set 

 with horns. 



The Fringed Dolphin Shell (D. laciniata, Lam.) is a good 

 example of a striking but not very abundant genus. The outer 

 coil is scarcely joined to the one above it, the apex is flat, and the 

 keeled whorls are armed with spines and hollow horns of different 

 sizes, set in parallel rows. The ground colour is white; the 

 projections all dark red, purplish or black. The lining is pearly. 

 Diameter, 3 inches; altitude, 2 inches. 



This Oriental species varies exceedingly in form, colour and 

 sculpture, as does the whole genus. 



Habitat. — Philippines. 



219 



