CHAP. XIV.] THE NEOTROPICAL REGION. 41 



Lizards are mucli more numerous, and there are several pecu- 

 liar and interesting forms. Three families are represented ; 

 Teidie by two genera — Callojjisfcs peculiar to Chili, and Amciva 

 which ranges over almost the whole American continent and is 

 found in Patagonia; Geckotidffi by four genera, two of wliich, — 

 Ca udivcrhcm iuid Homonota — are peculiar to Chili, while SpJue- 

 rodactylus and Cuhina are Neotropical, the former ranging to 

 I\atagonia, the latter to Chili ; and lastly the American family 

 Tguanidce represented by eight genera, no less than six being 

 peculiar, (or almost so,) to the South temperate region. These are 

 Lciodera, DiiJlolmmus and Proctrotretus, ranging from Chili to 

 Patagonia; Leiolcemus, from Peru to Patagonia; Phrymatnrus, 

 confined to Chili, and Ptygodcrus peculiar, to Patagonia and 

 Tierra del Fu ego. The other two genera, Oplurus and Lciosaurus, 

 are common to Chili and tropical South America. 



Tortoises appear to be scarce, a species of Hydromcdusa only 

 being recorded. Of the ximphibia, batrachia (frogs and toads) 

 alone are represented, and appear to be tolerably abundant, 

 seventeen species having been collected by Mr. Darwin in this 

 sub-region. Species of the South American genera Phrjjniscus, 

 Hylai)k'sia, Tdmatohius, Cacotus, Hylodes, Cyclorliainphus, Pleu- 

 rodema, Cystignathus, and Leiuperus, are found in various locali- 

 ties, some extending even to the Straits of Magellan,' — the 

 extreme southern limit of both Eeptilia and Amphibia, except 

 one lizard (Ptygoderus) found by Professor Cunningham in Tierra 

 del Fuego. There are also four peculiar genera, PJiinodcrma 

 belonging to the Engystomidte ; Alsodes and Nannophrync to the 

 Bombinatoridie ; Opistliodclphys to the Hylidas ; and Calyptoce- 

 2)h(di(s to the Discoglossidro. 



It thus appears, that in the Peptiles all the groups are typically 

 American, and that most of the peculiar genera belong to families 

 wliich are exclusively American. The Amphil»ia, on the other 

 hand, present some interesting external relations, but these are 

 as much with Australia as with the North temperate regions. The 

 Bombinatoridie are indeed Palasarctic, but a larger proportion are 

 Neotropical, and one genus inhabits New Zealand. The Chilian 

 genus Ccdyptocephalus is allied to Australian tropical genera. 



