ZOOLOGICAL GARDENS. 
141 
genus Tortrix , already mentioned in connection with 
their allies, the Pythonida , is the type. The next group 
of snakes is represented in India by a serpent which 
having also a thick tailor is likewise called two-headed, 
and this is the species which is so common in the Punjab 
and so generally seen with jugglers. It is one of the 
Sand Snakes, Erycidce , and the species referred to is 
Eryx johnii , and like the Pythons and Tortrix this 
Family of snakes has rudimentary hind limbs. Closely 
allied to these are the Rough-tailed snakes, or Uropeltidce . 
All the foregoing serpents are of a low type of structure 
and are generally distinguished either by the shields on 
the under surface of the body being awanting, or, if present, 
by being very narrow as compared with those on other 
snakes of a higher organization. As a rule, also, the 
head shields, if present, are not arranged as in the 
common serpents. The next group, the Dwarf snakes 
and their allies, the Bush and the Ringed snakes form 
sections of the great Family Cohibridcc , the members 
of which are all distinguished by their heads being 
quite distinct from their necks and covered with plates ; 
by their numerous teeth ; by two rows of scales on 
the under surface of the tail ; and by the absence of any 
vestiges of limbs. A familiar example of the Cohibridce 
is the common Grass snake of India, Tropidonotus stolatus , 
and another is the Damun , Ptyas mucosus, which the natives 
of India say has the habit of sucking cows. Both of 
these species are exceedingly common in Bengal, and 
are generally exhibited here as examples of harmless Colu- 
brides. Many snakes, such as Ptyas mucosus and also the 
very common Bengal snake, Tropidonotus quin cun ciatus, 
take freely to water, although they do not merit the name 
