H2 TYPES OF ANIMAL LIFE 



A little less than twenty years ago, there were a 

 number of axolotls living in the Jardin des Plantes at 

 Paris, under the care of a very intelligent keeper. One 

 day to his astonishment he missed one of his axolotls, 

 but found in its place a very different-looking eft, and 

 one without any gills. A little later the same thing 

 FIG. 31. happened in the case of several 



of them, and thus it became 

 known that the axolotl is but a 

 big and precocious baby, ready 

 to change rapidly, under certain 

 conditions, into the form of an 

 amblystoma. This change is a 

 very remarkable one, because 

 it by no means consists merely 

 in the loss of the gills, but 

 involves changes in the bones 

 of the skull, the number and 

 arrangement of the teeth, as 

 well as other important struc- 

 tural transformations. The 

 change was the more singular 

 because, although the unchanged 

 axolotls continued to breed 

 freely in their immature con- 

 dition without any care or 

 trouble to their keeper, none 



THE AXOLOTL. Q f the trans f orme d QIICS COuld 



be induced by any effort of his to do so. It seemed 

 as if they had, on obtaining maturity, discarded all con- 

 jugal family feelings as mere follies of youth. 



This curious change in the axolotl, and its long persist- 

 ence in breeding in a condition which, as far as form 

 and structure go, must be regarded as an immature one, 



