GENERAL STRUCTURE AND ORDERS. 



IO4I 



guished by the presence of a maxilla, and of five digits to the 

 feet. 



Families Sirenid^e and Proteidte. — Siren (fig. 971, a) and 

 Proteus, together with Menobranchus {ibid., c) are characterised by 

 the persistent gills, the absence of maxillae, the amphicoelous verte- 

 brae, and the reduction of the number of the digits below five ; Siren 

 differing from the other two by the absence of pelvic limbs. No 

 fossil representatives are known. 



Family AMPHiUMiDiE. — In this family the gills are shed, and 

 maxillae are present ; but' it agrees with the two last in the amphi- 

 coelous vertebrae, the cartilaginous carpus and tarsus, and the ab- 

 sence of eyelids. In the typical North American genus Amphiuma 

 (fig. 971, b) the body is much elongated, and the limbs are very 

 short. Another American genus is Menopoma, allied to which is 

 Megalobatrachus (Cryptobranchus or Sieboldid), typically represented 

 by the Gigantic Salamander (M. maximus) of China and Japan, and 

 in which we may probably include the large Salamander (fig. 972) 

 from the Upper Miocene of Switzerland, originally regarded as 

 human, and subsequently described under the name of Andrias. 



Family Salamandrid^e. — The true Salamanders lose their gills, 

 although there are instances, as in Amblystoma (Siredon), where 

 they persist in some individuals. Eyelids are present ; the vertebrae 

 are generally opisthoccelous ; and the carpus and tarsus more or less 

 ossified. This family is now represented in Europe by the Sala- 

 manders (Salamandra) and Newts (Molge or Triton). In a fossil 

 state the existing Molge cristata (fig. 973) occurs in the Norfolk 



Fig. 973. — The Crested Newt {Molge cristata). 



Forest-bed, and representatives of this genus have also been recorded 

 from the Middle and Lower Miocene of the Continent. The latter 

 deposits have also yielded remains referred to Sa/amandra, while the 

 name Chelotriton has been applied to an imperfectly known form from 

 the Lower Miocene of St Gerand-le-Puy, in Allier. Heliarchon, from 

 the corresponding strata of Rott, near Bonn, is allied to Salamandra, 



-a nd may not improbably be identical with Cheiotritwt. Megalo- 



