DIVISIONS OF EEPTILIA. 269 



(4.) The Culiibrina comprise a great number of altogether innocuous Snakes, 

 in which the superior maxiU.Ti are proviiled with solid teeth only, and there 

 are no fangs. The head in the Colubrine Snakes is not much wider tlian the 

 neck, and is covered with large shields (fig. 193, B). Tlie Colubrine Snakes 

 are cosmopolitan in their distribution, and an excellent example is the common 

 Kinged Snake [Coluber or Tropidonotus natrix) of Britain, a [lerfectly harmless 

 animal, which is commonly found iu damp situations, and whicli lives mainly 

 upon frogs. Closely allied to this is tlie Black Snake {Dascanion constriHor) 

 of North America, wlaich a.ttains a length of from three to five I'eet, but is 

 perfectly harmless, so far as man is concerned. 



(5.) The Pythonina comprise the well-known serpents termed the Boas, 

 Pythons, Anacondas, and Rock-snakes. The memliers of this group are the 

 largest of all living Snakes, attaining a length of certainly over twenty feet. 

 Their bite is not venomous, but they are nevertheless highly dangerous and 

 destructive animals, owing to tlieir great size and enormous muscular power. 

 They seize their prey and coil themselves round it in numerous folds, by 

 tightening which tliey gradually reduce tlieir victim to the condition of a 

 shapeless bolus, fit to be swallowed. The dental apparatus is extremely 

 powerful giving a firm hold for the constriction of the prey. They possess 

 rudimentary hind-liniljs, terminating in horny anal spurs, which co-operate 

 with the preliensile tail in enabling the anim.al to suspend itself from trees. 

 The true Boas and Anacondas are Soutli Anierican, but the Pythons are 

 inhabitants of Southern Asia and Africa, 



Order III, Lacertilia, 



The third order of Rejitiles is that of the Lacertilia, comprising all 

 the animals whicli are properly known as Lizards, together with 

 some snake - hke creatures, such as the Blind-worm, They are 

 distinguished by the following cliaracters : Usually tliere aie two 



Fig. 194.— T'4Hana. 



pairs of well-developed limbs, bnt tliere may be only one pair, or all 

 the limbs may be rudimentary. In all cases, however, a scapular 

 arch is present. The vertebrre are usually hollow in front {procosl- 

 nns), rarely hollovv' at both ends (amphircelous). In no living Lacer- 



