ITS 2 



YEltTEBltATE ANIMALS. 



stoma. Moreover, in one species (viz., Amhli/stoma mavortium), this 

 cliange is known to occur in a state of nature ; the larva being an 

 Axolotl, witli gills, and capable of breeding, but ultimately' changing 

 to a gill-less Salamander. 



Tlie Proteiis is an extraordinary Amphibian whicli is found in- 

 habiting the waters of caves iu lUyria and Dalmatia. It attains a 

 length of about a foot, and is of a pale fiesh-colour or nearly white. 

 The gills, which are retained throughout life, are of a bright scarlet. 

 Both pairs of limbs are developed, but they are only short and 

 weak, the foredimbs having three toes each, and the hinddimbs only 

 two. The e3'es are r\idimentary, the animal spending its existence 

 in darkness ; and swinmiing is effected mainly by means of the tail. 

 Allied to Proteus is the Mud-puppy {Menohranchus, fig. 181, C) of 



Fig. ISl.— T:iil'-il Ainpliihiaiis. A, Si mi li'reiiiiia; R, Ampliivmn, s1in\viii,LC l:lie fnnr 

 liiiiiHtt linil.s; C, Mnij'hraiiehiis mncnliilvs. (After Miv.irt.) 



North Araerici, which is from six inches to a foot in length. The 

 Siren or Mud-eel (fig. 181, A) is a large lizard-like Am]iliibian, 

 which is founil abundantly iu the swanijis of 8outh (.'arolina, and 

 attains the great length of three feet. The external Ijrancliia^ are 

 retained througliout life, and they are the main organs of resjiira- 

 tion. The foi'e-linibs ai'o piescnt, but the hinder |iair of limbs is 

 never di;velo]ied. 7\nother form, which occurs in the Southern 

 Uniti'il States, is the ( 'ongo-snaki! (A ui/i/iiumii). This h.is a snake- 

 bke body, witli ruilimenliiry two-toed limbs (fig. 181, B), and thougli 

 the gill-sbts lemain on the side »( the neck, it has no gills. 



