chap, xiv.] THE NEOTROPICAL REGION. 11 



Cdestus and Diploglossus (Scincidae) ; Sphccrodactylus (Gecko- 

 tidae) ; Lioccphalus, Liolccmus, Proctotretus, and many smaller 

 genera (Iguanidae). The three extensive Old World families 

 Varanidaa, Lacertidae, and Agamidae, are absent from the entire 

 American continent. 



In the order Crocodilia, America has the peculiar family of 

 the alligators (Alligatoridae), as well as several species of true 

 crocodiles (Crocodilidae). The Chelonia (tortoises) are repre- 

 sented by the families Testudinidae and Chelydidae, both of wide 

 range ; but there are six peculiar genera, — Dermatemys and Stau- 

 rotypus belonging to the former family, — Peltoccphalus, Podo- 

 cnemis, Hydromedusa, and Chelys, to the fatter. Some of the 

 Amazon river-turtles of the genus Podocnemys rival in size the 

 largest species of true marine turtles (Cheloniidae), and are equally 

 good for food. 



Amphibia. — The Neotropical region possesses representatives 

 of sixteen, families of Amphibia of which four are peculiar; all 

 belonging to Anoura or tail-less Batrachians. The Caeciliadae 

 or snake-like amphibia, are represented by two peculiar genera, 

 Siplwjwpsis and Bhinatrcma. Tailed Batrachians are almost 

 unknown, only a few species of Spelerpes (Salamandridae) enter- 

 ing Central America, and one extending as far south as the 

 Andes of Bogota in South America. Tail-less Batrachians on 

 the other hand, are abundant ; there being 14 families repre- 

 sented, of Which 4, — Rhinophryndae, Hylaplesidse, Plectroman- 

 tidae, and Pipidas are peculiar. None of these families contain 

 more than a single genus, and only the second more than a 

 single species ; so that it is not these which give a character to 

 the South American Amphibia-fauna. The most important and 

 best represented families are, Ranidae (true frogs), with eleven 

 genera and more than 50 species ; Polypedatidae (tree-frogs) 

 with seven genera and about 40 species ; Hylidae (tree-frogs) 

 with eight genera and nearly 30 species ; Engystomida? (toads) 

 (5 genera), Bombinatoridae (frogs), (4 genera), Phryniscidae and 

 Bufonidae (toads), (each with 2 genera), are also fairly represen- 

 ted. All these families are widely distributed, but the Neotropi- 

 cal genera are, in almost every case, peculiar. 



