CYPRAEA COWRY. 69 



of shape, delicate and distinct markings, with 

 great beauty and variety of colours. They are 

 readily distinguished from all other shells by 

 their lips being rolled inwards, and both of 

 them toothed. The history of the genus is very 

 interesting from the remarkable difference which 

 occurs in the appearance of the same shell at 

 the various stages of its growth. In its earliest 

 state, the shell is very thin, almost colourless, 

 and dull ; the mouth rather wide, the outer lip 

 not rolled inwards, but having a sharp edge, and 

 neither lip denticulated. The shell which the 

 animal first forms is indeed so dissimilar to the 

 perfect Cypraea that it was formerly placed in 

 another genus. In the second, or intermediate 

 period of growth, the shell begins to approach 

 the general form that characterizes the genus. 

 The lips are curved inwards, and the teeth be- 

 come apparent; but the shell is still thin, its 

 colour faint, and its markings seldom more than 

 ill-defined tranverse bands. In its third and per- 

 fect state, the Cypraea has received an addi- 

 tional coating of testaceous matter, the pattern 

 appears with its vivid tints, and delicate mark- 

 ings, and the spire if not entirely hidden, yet 

 scarcely projects out of the body whorl. 



The animal itself undergoes a considerable 

 change during its growth, its mantle at first is 

 small, but it increases with its age, and expands 

 at the sides into two ample wings ; from these it 

 is that the final layer which completes the shell 

 is deposited. In the adult specimens, these ex- 



