1919.] The Occurrence of Cyprea nivosa Broderip. 141 
of Cyprea vitellus. The line of junction of the mantle-lobes, 
well developed in C. nivosa, is seldom observed in C. vitellus. 
h ; 
in C. niv 
verse cracks in the ventral and marginal portions of the en- 
amelled callosity, which are observed in many species of Cyprei- 
nivosa: it is a somewhat thicker, more ponderous shell. The 
At equal dimensions the apertural denticulations of Cyprea 
vitellus are fewer than those of Cyprea nivosa: for instance, 
the outer and columellar lips carry respectively twenty-one and 
nineteen ridges in a specimen 0 itell 
63 x 4] x 35 mm. 
ConcLuDING REMARKS. 
According to Melvill (op. cit., p. 206), Cyprea nivosa is 
ee been known only from Ma 
is idle, for the present, to discuss whether its distribution is dis- 
continuous or not. The species is € ple 
one ; yet, owing to its curious similarity to C. vitellus, it is not 
impossible that there may have been other examples of the 
confusion of which we have here an instance, and that the spe- 
