SEA SERPENTS 
lobed liver is really made up of two lobes, though they 
are closely adpressed. In the same way other organs 
are contained in other compartments. The lizards’ 
, body cavity and viscera suggest a scantily filled and 
loosely packed portmanteau ; that of the lizard a full 
and closely packed box. 
Snakes are quite as numerous as lizards, and have 
much the same range ; they are, like the lizards, parti- 
cularly abundant in the tropics. Iceland, as we all 
know, has no snakes, and generally speaking, as with 
lizards, they wane in numbers towards the north. The 
three British snakes, viz. the grass snake (Tvopidontus 
natrix), the smooth snake (Coronella austriaca), and the 
viper (Vipera berus), are almost, if not quite, always on 
view at the Zoo. As with lizards, there are terrestrial, 
arboreal, aquatic, and even marine snakes. But the 
marine snakes are much more marine than is the iguan- 
oid lizard, Oveocephalus, which lives largely in the sea 
off the Galapagos. Such genera as Distiva, Hydrus, 
Platyurus, are, with a few exceptions, purely marine and 
pelagic, living at the surface of the ocean and preying 
upon fish. These snakes are hardly likely, from the 
nature of the case, to be seen at the Zoo. Besides these 
marine snakes a large number of serpents of various kinds 
spend a large part of their time in freshwater ponds, 
ditches, etc. For example, the North American water 
viper (Ancistrodon piscivorus), and even the common 
grass snake. At the opposite extreme is the desert- 
haunting Cleopatra’s asp (Cerastes cornuta), with the 
projecting and horn-like scale above each eye. Though 
whether the Egyptian queen did not avail herself of the 
African cobra (Nata haje) is a moot question. These 
desert snakes are, like the desert-loving lizards and 
mammals, and even birds, clad in desert colours. Ar- 
boreal snakes are exemplified by the boas, and by such 
types as the green viper, dealt with later. There are 
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