CHAP. XIV.] 
THE NEOTROPICAL REGION. 
1! 
Celestus and Diploglossus (Scincidae) ; S 'phcerodadylus (Gecko- 
tidse) ; Liocephalus, Liolcemus, Prodotretus, and many smaller 
genera (Iguanidse). The three extensive Old World families 
Varanidse, Lacertidse, and Agamidse, are absent from the entire 
American continent. 
In the order Crocodilia, America has the peculiar family of 
the alligators ( Alligator idse), as well as several species of true 
crocodiles (Crocodilidee). The Chelonia (tortoises) are repre- 
sented by the families Testudinidas and Chelydidae, both of wide 
range ; but there are six peculiar genera, — Dermatemys and Sfau- 
rotypus belonging to the former family, — Peltocephalus , Podo- 
cnemis, Hydromedma, and Chelys, to the latter. 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 Cseciliadae 
or snake-like amphibia, are represented by two peculiar genera, 
Siphonopsis and Ehinatrema. 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, Hylaplesidae, 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 ; Polypedatidse (tree-frogs) 
with seven genera and about 40 species ; Hylidee (tree-frogs) 
with eight genera and nearly 30 species ; Engystomidae (toads) 
(5 genera), Bombinatoridse (frogs), (4 genera), Phryniscidae and 
Bufonidse (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. 
