72 Beautiful Shells. 
somewhat stouter form, called exwstus—burned or 
scorched. Of the Poached-egg Cowries there are 
several species, the most common is called by 
naturalists Ovulum ovum, Fig. 4, from ovwm—an 
egg; the back of this shell is much elevated and 
rounded ; it is smooth and white; the inside is 
orange brown. Some of the Poached-egg group 
are of a more slender and angular shape, as, for 
instance, that called the Gibbous (0. Gibbosa) ; the 
moon when more than half-full, is called gibbous— 
that is, rounded unequally, as this shell. 
Few shells undergo greater changes, 
both of shape and colour, during the 
process of growth, than the Cowries, 
which are called in France Porcelaines, 
on account of their high polish and 

brilliant hues; a single species in dif- 
ferent stages of development might well be, and 
often is, taken for distinct shells. Much might be 
said about the Mollusks which inhabit them, but 
our present subject has rather to do with their outer 
covering than their internal structure. The most 
rare and valuable, if not the most beautiful of these 
Cowries, is the C. aurora, or aurantium, Morning- 
dawn, or Orange Cowry, a perfect specimen of 
which has been sold for fifty guineas. There isa 
