Masterpieces of Science 



These are of many distinct groups, and comprise 

 both venomous and harmless genera; but almost 

 all of them are of a beautiful green colour, some- 

 times more or less adorned with white or dusky 

 bands and spots. There can be little doubt that 

 this colour is doubly useful to them, since it will 

 tend to conceal them from their enemies, and 

 will lead their prey to approach them uncon- 

 scious of danger. Dr. Gunthner informs me that 

 there is only one genus of true arboreal snakes 

 (Dipsas) whose colours are rarely green, but 

 are of various shades of black, brown, and olive, 

 and these are all nocturnal reptiles, and there 

 can be little doubt conceal themselves during the 

 day in holes, so that the green protective tint 

 would be useless to them, and they accordingly 

 retain the more usual reptilian hues. 



Fishes present similar instances. Many flat 

 fish, as, for example, the flounder and the skate, 

 are exactly the colour of the gravel or sand on 

 which they habitually rest. Among the marine 

 flower gardens of an Eastern coral reef the fishes 

 present every variety of gorgeous colour, while 

 the river fish even of the tropics rarely if ever 

 have gay or conspicuous markings. A very 

 curious case of this kind of adaptation occurs 

 in the sea-horse (Hippocampus)' of Australia, 

 some of which bear long foliaceous appendages 

 resembling seaweed, and are of a brilliant red 

 colour; and they ar*e known to live among sea- 

 weed of the same hue, so that when at rest they 

 must be quite invisible. There are now in the 

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