54 ZOOLOGICAL GEOGRAPHY. [part hi. 



Cuculidse) ; Monasa (Bucconidae) ; many genera of Trochilidse ; 

 and Nothocercus (Tinamidse) ; none of which extend further 

 north. A considerable number of the peculiar genera noted 

 above, are also found in this restricted area, which is probably 

 one of the richest ornithological districts on the globe. 



Beptiles. — These are much less known than the preceding 

 classes, but they afford several peculiar and interesting forms. 

 Snakes are perhaps the least remarkable ; yet there are recorded 

 4 peculiar genera of Calamariidse, 1 of Golubridse, 1 of Homalop- 

 sidae, 3 of Dipsadidae ; while Boa and Maps are in common with 

 South America. Lizards are much more specially developed. 

 Chirotes, one of the Amphisbsenians, is confined to Mexico and the 

 southern part of the Nearctic region ; Heloderma forming a pecu- 

 liar family, Helodermidae, is Mexican only ; Ahronia and Barissia 

 (Zonuridae) are also Mexican, as is Siderolampus belonging to 

 the Scincidse, while Blephara/ititis (same family) inhabits Nicara- 

 gua ; Brachydactylus, one of the geckoes, is from Costa Eica ; 

 while Phymatolcpis, Laraandus, Corytheolus, Cachrix, Corytho- 

 phanes and Chamceleopsis, all belonging to the Iguanidae, are con- 

 fined to various parts of the sub-region. In the same family we 

 have also the Antillean, Cyclura,Sind the Nearctic Fhrynosoma and 

 Tropidolepis, as well as the wide-spread American genus Anolius. 



Among the tortoises, Staurotypus, allied to Chelydra, is found 

 in Mexico and Guatemala ; and another genus, Claudius, has been 

 lately described from Mexico. 



Amphibia. — These are chiefly Batrachians ; Ehinophryna 

 (forming a peculiar family) being confined to Mexico ; Triprion, 

 a genus of Hylidae, inhabiting Yucatan, with Leyla and Stra- 

 bomantis (Polypedatidse) found only in Costa Eica and Veragua, 

 are peculiar genera. The Salamandridae, so abundant in the 

 Nearctic region, are represented by a few species of Amblystoma 

 and Spelerpes. 



Fresh-water fish. — Since the British Museum catalogue was 

 published, a valuable paper by Dr. Giinther, in the Transactions 

 of the Zoological Society for 1868, furnishes much additional 

 information on the fishes of Central America. In that part of 

 the region south of Mexico, 106 species of fresh- water fishes are 



