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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 confined
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