chap, xiv.] THE NEOTROPICAL REGION. 41 



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

 liar and interesting forms. Three families are represented ; 

 Teidse by two genera — Callopistes peculiar to Chili, and Ameiva 

 which ranges over almost the whole American continent and is 

 found in Patagonia ; Geckotid* by four genera, two of which, — 

 Caudiverbera and Homonota — are peculiar to Chili, while Sphce- 

 rodactylus and Ciibina are Neotropical, the former ranging to 

 Patagonia, the latter to Chili ; and lastly the American family 

 Iguanidse represented by eight genera, no less than six being 

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

 Zeiodera, Diplolcemus and Proctrotretus, ranging from Chili to 

 Patagonia ; Leiolcemus, from Peru to Patagonia ; Phrymaturus, 

 confined to Chili, and Ptygodcrus peculiar, to Patagonia and 

 Tierra del Fuego. The other two genera, Opiums and Leiosaurus, 

 are common to Chili and tropical South America. 



Tortoises appear to be scarce, a species of Hydromedusa only 

 being recorded. Of the Amphibia, 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 Phryniscus, 

 Hylaplesia, Tclrnatobius, Cacotus, Hylodes, Cyclorhamphus, Pleu- 

 rodynia, 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, Bhinoderma 

 belonging to the Engystomidse ; Alsodes and Nannophryne to the 

 Bombinatoridse ; Opisthodelphys to the Hylidse ; and Calyptoce- 

 phalus to the Discoglossidae. 



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

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

 which are exclusively American. The Amphibia, on the other 

 hand, present some interesting external relations, but these are 

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

 Bombinatoridje are indeed Palsearctic, but a larger proportion are 

 Neotropical, and one genus inhabits New Zealand. The Chilian 

 genus Calyptoccphalus is allied to Australian tropical genera. 



