CROCODILES, ALLIGATORS, G A VIALS. 583 



restrial, but not a few readily take to the water, and there 

 are many habitual sea serpents. 



The serpent still bites the heel of progressive man, the 

 number of deaths from snake bite in India alone amounting 

 to many thousands yearly, though there can be little doubt 

 that the snakes are often innocent scape goats. 



True Ophidians first occur in Tertiary strata. 



Classification of Ophidia. 

 Sulj-order I. Typhlopidie. The lowest and most divergent Ophidians, 

 occurring in most of the warmer parts of the earth, generally 

 smaller than earthworms, usually subterranean burrowers, with 

 eyes hidden under scales, with a non-distensible mouth, wdth 

 teeth restricted either to the upper or to the lower jaw. " The 

 palatine bones meet, or nearly meet, in the base of the skull, 

 and their long axes are transverse ; there is no transverse 

 bone ; the pterygoids are not connected with the quadrates " 

 (Huxley). 



Example : — Typhlops, British India. 

 In all other Ophidians, the palatines are widely separated, and their 

 long axes are longitudinal ; there are transverse bones con- 

 necting palatines and maxillre ; the pterygoids are connected 

 with the quadrates. 

 Sub-order 2. Colubriformes (innocuous Snakes). The poison gland 

 is not developed as such ; the maxillary teeth are not grooved. 

 Examples ; — The British smooth snake [Coroiiella icevis), 

 the British grass snake ( TropiJoiwtiis natri.x), the Pythons, 

 the Boas. The Anaconda (Boa murina), which may 

 attain a length of almost thirty feet, is the largest living 

 Ophidian. 

 Sub-order 3. Colubriformes Venenosi. 



Examples ; — Cobras, Naja tripjtdians (Indian), Naja haje 

 (African); thttlama-(lryad{OpkiopAaoiis <;/a/j), eating other 

 snakes; Coral snakes (£/a/i.t,&c.) ; Sea. snakes [Hyi&op/iis, 

 &c.), with paddle-shaped tails. 

 Sub-order 4. Viperiformes. 



Examples : — The British adder (Pelias or Viperabenis) ; the 

 Rattlesnake (Crotahcs), with a rattle formed chiefly from 

 epidermic remnants of successive sloughings ; the African 

 Puff adder [Clotho arietaiis). 



CrocodilL'V. Crocodiles, Alligators, Gavials. 



General Character.s. — The Crocodilians are carnivor- 

 ous fresh ivater reptiles of large size, ?iow represented by three 

 genera — Crocodilus, Alligator, and Gavialis. 



The skin hears epidermic scales, underneath some of ivhich 

 there are dermic bones or scutes. 



