THE COLOURS OF COWRIES 353 



more pronounced, and in a half-grown specimen of the 

 same species is so elongated as to project considerably 

 beyond the hinder extremity of the shell. Moreover, in 

 immature examples of this species the hinder extremity 

 of the right margin of the shell is expanded into a wing- 

 like extension, recalling the wing-shells, or Strombidae. 

 In both the adult and the young of Scott's cowry the 

 coloration is very similar ; but in the young of the Surinam- 

 toad cowry there is a difference both in form and in 

 colour from the adult. In form the shell has a distinct 

 spire, and a thin outer lip ; and in still younger examples 

 these characters are more exaggerated, the mouth being 

 entirely devoid of teeth, and the outer lip quite thin and 

 sharp. Again, whereas the upper surface of the adult 

 shell has a broad dark brown margin, and the central 

 area spotted with light brown on a ground of dark 

 brown, the young exhibits dark and light transverse bands, 

 with a certain amount of mottling. 



Young cowries, then, are much more like ordinary shells 

 than are the adults, and clearly indicate that the latter 

 belong to a highly modified or specialised type. The 

 alteration is produced by the expansion of the mantle- 

 lobes of the adult, which deposit a shining enamel over 

 the entire shell, eventually concealing more or less com- 

 pletely the spire, and thus totally modifying the original 

 form. A young cowry is, indeed, much more like an olive 

 or a melon-shell ; but, as a matter of fact, neither of the 

 two latter are the nearest relatives of the Cypraeidae, among 

 which are the Strombidae, or wing-shells. And in this 

 connection the near resemblance of the young of Scott's 

 cowry to a wing-shell is decidedly worthy of note, as 

 suggestive of a direct affinity between the wing-shells and 

 the cowries. 



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