THE AMPHIBIA 243 



often leaving the ponds and ditches after the breeding season and 

 wandering about in the rank, wet herbage of water meadows, and 

 sometimes finding its way into cool cellars and out-buildings. 



The Spotted Salamander (Salamandra mctculosa) has a large, 

 thick head and rather clumsy body, with numerous warty growths 

 on the sides, while the tail is cylindrical at its outer end. It is 

 black in colour, with yellow spots. It is a land dweller in the 

 adult state, frequenting cool, damp places, and feeding upon 

 insects, worms, and slugs. 



One of the most interesting Mexican Amphibians is the so- 

 called " Axolotl," which is the larval form of AmUystoma tigrinum. 

 The colour is a dark grey, almost black, and in the Axolotl stage 

 the animal has three pairs of delicate, much-branched external 

 gills, and a flat, long tail with a broad ventral and dorsal fin, the 

 latter extending along the back almost to the neck. To quote 

 Dr. Hans Gadow : " For many years these creatures were looked 

 upon as a species of Perennibranchiata under the generic name 

 of Siredon, although Cuvier suspected that they were but the 

 larvae of an otherwise unknown terrestrial Urodelct. The mystery 

 was not cleared up until the year 1865, when some Axolotls which 

 had been kept for a year in the Jardin des Plantes at Paris sud- 

 denly began to pair, and laid eggs which within six months developed 

 into full-sized Axolotls. This certainly looked as if these creatures 

 were not larvae, but a true Perennibranchiate species. But to the 

 general surprise several of these young Axolotls gradually lost 

 their gills, the clefts closed up, the fins of the back and tail dis- 

 appeared, the head became broader, the creatures left the water 

 permanently, and, in fact, turned into the already well-known 

 terrestrial AmUystoma tigrinum. The other brothers and sisters 

 of the same brood remained aquatic Axolotls, which thereby 

 revealed themselves after all as the larval and not as the perfect 

 stage of this remarkable species/' The natural causes which lead 

 to this species of AmUystoma frequently remaining throughout 

 life in the larval state, but developing generative organs, are not 

 yet clearly understood. 



The Sirenida, or Sirens, are Amphibians with long bodies and 

 short limbs, the hind limbs being deficient in some. The Siren, 

 which frequents the stagnant waters and marshy ground of South 

 Carolina, is an olive or deep greenish- black coloured, eel-shaped 



