354 MOSTLY MAMMALS 



Turning now to the interesting problem of coloration, 

 the first feature that must strike the observer is that the 

 pattern developed on the shells of most cowries is not 

 seen by the animals themselves, for the reason that by 

 the time the creature is fully protruded from its shell, 

 the upper surface of the latter is more or less completely 

 concealed by the fleshy lobes of the mantle. Accordingly, 

 it would seem to be apparent that the colouring of these 

 molluscs is developed for the purpose of protection, and 

 not for the admiration of the different individuals or 

 sexes of the same species. It might, indeed, be urged 

 that as the lobes of the mantle are coloured similarly to 

 the shell, or even more intensely, the colours are visible 

 to the animals, and are therefore designed for mutual 

 admiration. But had this been the object, it would surely 

 have sufficed to restrict the coloration to the outer surface 

 of the mantle-lobes, and not to have extended it on to 

 their inner surfaces, from which it is deposited on the 

 shell. As regards the utility of the cowry type of colora- 

 tion for protective purposes, I have never had the 

 opportunity of seeing the living molluscs in their native 

 haunts, nor have I come across any description from those 

 who have. Cowries, which are mostly tropical or sub- 

 tropical molluscs, are, however, described as living in 

 shallow water not far from the shore, and feeding on 

 zoophytes ; and so far as one can judge, their colours 

 ought to harmonise well with the hues of the denizens of 

 a coral-bank, or a mass of sea-anemones, many of which 

 are more or less similarly spotted. If this explanation 

 prove to be the true one, we can readily see why both the 

 shells and the hard parts of cowries partake of the same 

 striking types of coloration. 



Turning now to the consideration of the various types of 



