CANNIBAL TADPOLES 



These tadpoles are very carnivorous, and feed upon 

 minute water crustaceans. The black tadpoles of the 

 British puddle eats decaying vegetation, though on 

 occasions it will become a pure cannibal. At the sides 

 of the mouth of the Plaathande tadpole are a pair of 

 very long feelers, which must be tactile, and when first 

 described led the describer to place the animal as an 

 adult creature in the neighbourhood of some of the 

 Siluroid fishes, whose heads are beset with such ten- 

 tacles. In the Xenopus tadpole the tentacle gets less 

 and less important with advancing days, and finally 

 remains in the adult as a small process under the eye, 

 which can be recognised in the illustration. 



THE FRESH-WATER SIREN. 



Since the year 1876, when the first example was 

 received, there have been always, or at any rate gene- 

 rally, specimens of this newt-like and American creature 

 in the Zoological Gardens. The siren (Siren lacertina), 

 eel-like though it appears, belongs to the great group of 

 the amphibia ; like the Japanese newt (Megalobatrachus), 

 like the little English newt, and the axolotl it belongs 

 to that division of the amphibia known as the Urodela, 

 from the fact that they have tails, which the frogs and 

 toads have not. All these tailed Batrachia are inhabi- 

 tants of the temperate regions, only just getting into 

 South America, not reaching tropical Africa, and totally 

 absent from Australia and its adjacent and heated 

 islands. It is not indeed too much to say that they 

 represent in cooler waters the tropical mud-fishes, Cera- 

 todus, Lepidosiren, and Protopterus. Where there are 

 Dipnoi there are no tailed amphibians and vice-versa. 

 As it is not unreasonable to trace the origin of the tailed 

 amphibians, which are clearly the most primitive of 

 existing amphibians, from some dipnoid form, these 



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