DISAPPEARANCE OF LIMBS 



facts are not without interest. Why this black and 

 slimy newt should be called Siren is not clear. They do 

 not chirp or sing, and indeed are voiceless, like other 

 newts. They are not enchantresses and do not play on 

 cords. On the contrary, they are black and evil-looking, 

 not alluring except indeed to the naturalists, to whom 

 they present many points of interest. This animal 

 grows to about two feet in length, and lives exclusively 

 or at least very nearly entirely, in muddy ditches, where 

 it finds its animal prey. The accurate John Hunter 

 was the first to detect the real nature of the siren, and 

 placed it between amphibians and fishes. A retrograde 

 step was taken by Camper the Dutchman, who called it 

 a mursena, or eel, an error which is perpetuated to-day 

 by its vernacular name of " Mud-eel," The siren has 

 external fringed gills like the axolotl. But there is no 

 reason to suppose that it is, like the axolotl, a larval 

 form ready to blossom out into a more fully formed and 

 gill-less newt when forced to leave its streams. For in 

 the first place its degradation is shown by the missing 

 hind limbs, and in the second place it has a set of larval 

 gills which give place to the therefore permanent gills 

 of the adult. It has had its chance as a larva, and has 

 failed to take advantage of it. As with other aquatic 

 creatures, it is .the hind limbs which have gone. Thus 

 the whales have not a trace of these : and in the seal 

 and sea-lions they are more or less bound up with the 

 tail, and clearly on the wane. In terrestrial animals 

 which have undergone degeneration, it is rather the 

 fore limbs that go first, as witness the snakes and many 

 tail-less lizards. 



THE AXOLOTL 



There is nothing more interesting at the Zoo than the 

 swarthy American newts, called axolotls, unless it be 



294 



