DISTEIBUTION OP OPHIDIANS. 
217 
the Langaha, an anomalous and very curious species of 
Dryiopliis, the Herpetodryas Goudotii, and H. rhodogas^ 
ter, the Dipsas Gaimardi ; all peculiar to Madagascar. 
The Mascarine Isles produce a very handsome Coluber, 
C. miniatus, and a small Boa of a gracile form, and slender 
tail (Boa Dussumieri). Only a single serpent of the genus 
Psammophis is known in the Seychelles. 
If we except the two Indian peninsulse, Asia is not very 
abundant in reptiles. This observation would appear 
correct, although some other parts of Asia have not been 
so often explored as those already named. This is readily 
explicable by the position of Asia, a large portion of 
which is situate in the temperate and frigid zones, re- 
gions little favourable to the multiplication of reptiles. 
Northern Asia, or rather Siberia, produces a great many 
animals that occur also in Europe ; and the same holds 
good with serpents.* A curious Ophidian, peculiar to 
the southern parts of Siberia, is the Trigonocephaliis 
halys, intermediate in structure between the Vipers of 
Europe, and the Trigonocephali with plates covering the 
head. The deserts south of the Caspian Sea, which are 
prolonged to the borders of Hindustan, on the one hand, 
and, on the other, stretch by Iran to Arabia and Syria, 
to join those of Africa, produce a small number of rep- 
tiles, which equally inhabit the similar deserts of the lat- 
ter continent. There have been observed the Monitor 
exanthematicus, the Stelliones, the Agama of the desert 
(Lacerta aurita, Pallas), the Vipera echis, the Psammophis 
lacertina, and the Eryx, which extends to Siberia, but 
forms in India one or more local varieties or distinct 
races. We are in absolute ignorance with regard to the 
reptiles of the rest of Central Asia ; but the known ani- 
mals of China, at least those of the neighbourhood of 
Canton, often present a strong analogy to the productions 
of the Islands of the Great Indian Archipelago. Before 
^ Most travellers agree that our Tropidonoti, our Viper, our Lizards, 
&c., are found in Siberia ; but not admitting facts into my work that are 
not founded on dissections of the subjects themselves, or on good figures 
of the animals, I have but rarely availed myself of the remarks of tra- 
vellers. 
r 
