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irregular ; of two living under exactly the same conditions, 

 one attained three times the size of the other, while later on 

 the backward one would in his turn gain upon his brother. 

 The power of endurance of these animals is extraordinary ; I 

 have left them in the shallow pans for hours in the blazing 

 sun ; they have remained in the same way out of doors for 

 weeks together in winter, being at one time frozen into a mass 

 of solid ice. They have passed weeks without food, when 

 worms were difficult to procure,* and a number were left in 

 a small aquarium out of doors from April to October without 

 any visible supply. The impurity of the water when un- 

 changed did not affect them, and I never lost one by a 

 natural death. They seem to have, to a very great degree, 

 the power of adapting themselves to circumstances. The 

 time of full growth in the case of Dumeril's specimens seems 

 to have been from seven to twelve months. But in this case 

 the animals were kept at a uniformly high rate of temperature 

 in the Reptile Vivarium at Paris, and were regularly supplied 

 with abundance of suitable food. My own specimens which 

 have had a very different treatment, are not much more than 

 half grown, although they are nearly three years old. 

 Madame Carbonnier, the Pisciculturist, of Paris, informs me 

 that with her Axolotls will breed in two years, but continue 

 to increase in size for three. 



Like our own Triton the Axolotl is sluggish and disin- 

 clined to feed when the temperature is under 55°. They 

 take food at short intervals, but not much at a time, for 

 though their gape is enormous their throats and stomachs 

 are comparatively small. I suspect that in their native 

 state they live on the small fry which swarm in the tepid 

 shallows of the Mexican waters. 



I must allude to the power which the Axolotl, in common 

 with other Urodela, has of reproducing its limbs when 

 damaged. Without having resort to the cold-blooded experi- 

 ments of the French savants who vivisected them bit by bit, 



* The adults were fed on worms ; they also took slugs very readily. 



