/]'. VERTEBllATA: REPTILIA, CROCOJJILIA. 



001 



mentary or even absent. In tlie Typblopliida', on the other hand, the right 

 appears to be degenerate. The urinary bladder is always absent. The 

 excreta, chiefly nrio acid, accumulate as a solid mass in the cloaca and 

 form the chief part of the excrement ; the faeces, on account of the 

 extraordinary digestive powers, being small in amount. 



Section I. Opoterodonta (Angiostoma). Burrowing blind tropical 

 snakes with the mouth incapable of distension, the animals living on 

 small insects. TypJilojM. 



Section 11. Peuopoda. These large snakes have paired lungs and rudi- 

 ments of hind extremities ; lack poison fangs, and kill their prey by mus- 

 cular power. Python, Africa ; Boa and Bunedes (anaconda). South 

 America. 



Section III. Colubrifoumia. Ordinary snakes (over 500 species) with 

 numerous teeth in the upper jaw, Init with appendages entirely aljsent. 

 Some are poisonous, some not, Vjut no structural lines can be drawn be- 

 tween them. The Aglypha have no grooved teeth. Tropidoiwtns* water 

 snakes; Ba^canion, * h\ack snakes; Eutainia,* garter snakes. Tlie Pro- 

 teeogltpha, with grooved teeth, perma- 

 nently erect, arc poisonous. Most are 

 brightly colored. Elaps,* the coral snake; 

 Waja tripudians, the cobra of India ; JV. 

 Jiaje, Cleopatra's asp. Here belong the 

 pelagic sea snakes of the Indo-Paoitic, 

 which are vivii)arous. 



Section IV. Sole.n'oglypha. With the 

 maxilla reduced and serving as a socket 

 for the single large tubular tooth with 

 one or more reserve teeth (tig. 627). 

 ViPEEiD^, Old AVorld, no pit between 

 nostril and eye. Orotalid^, New World 

 and Asia, with a pit between nose and 

 eye. C'wtalus* with the tail ending in 

 a rattle formed by remnants of cast skins, 

 is common throughout the United States. 

 Aykistrodon contortri.r* copperhead, 

 and A. piscivorus, moccasin, lack the 

 rattle. Bothrops lanceolatus of the An- 

 tilles, possibly the most poisonous snake. 



Order VIII. Crocodilia (Loricata). 



'I'he crocodiles, alligators, etc., 

 agree with some of the form.s already 

 mentioned in the oval cloacal open- 

 ing with single copulatory organ, 

 immovable quadrate, and the bony 

 jilates in the skin. In shape they are 

 lizard-like, but in structure they differ from all otlier living reptiles 



Copf 



Fig. 6;i0.— Ventral snrfar-c o( skuU 

 of crocodile. ( From ^Vierl^'rslluirn.) 

 Cofc, occipital condyle: T'/f, clio- 

 ana ; ,/f/, jn^al ; 3/, maxillary ; f Wf, 

 t^asioccipital ; Or/', orbit ; (,>i, quad- 

 rato,jugal : i.^\i, quadrate ; V\, pala- 

 tine ; Vxnx, premaxilla; Ft, ptery- 

 goid; T.s, transversum. 



