482 REPTILES. 



and symbolise the power of the earth, 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. 



Sub-order I. Typhlopidse. 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, with 

 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 maxill^^ ; 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 (Coronella Irevis), 

 the British grass snake ( Tropidonotus natrix), the Pythons, 

 the Boas. The Anaconda {Boa tnurina), which may 

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

 Ophidian. 

 Sub-order 3. Colubriformes Venenosi. 



Examples : — Cobras, Naja triptidians (Indian), Naja haje 

 (African) ; the Hamadryad ( Ophiophagus elaps), eating other 

 snakes; Coral-snakes (5'/a;)j, etc. ); Sea-snakes (.^rf;-o//5zV, 

 etc.), with paddle-shaped tails. 

 Sub-order 4. Viperiformes. 



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

 Rattle-snake (Crotalus), with a rattle formed chiefly from 

 epidermic remnants of successive sloughings; the African 

 Puif-adder {Clotho arietans). 



Order Crocodilia. Crocodiles, Alligators, Gavials. 



The Crocodilians are carnivorous fresh-water reptiles of 

 large size. They are now represented by three genera — 

 Crocodilus, Alligator, and Gavialis. ' 



