IV. VERTEBRATA: REPTILIA, CROCODILIA. 



601 



mentary or even absent. In the Typhlophidae, on the other hand, the right 

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

 excreta, chiefly uric 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. Typhlops. 



Section II. PEROPODA. 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 Eunectes (anaconda), South 

 America. 



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

 numerous teeth in the upper jaw, but with appendages entirely absent. 

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

 tween them. The AGLYPHA have no grooved teeth. Tropidonotus,* water 

 snakes; Bascanion,* black snakes; Eutainia,* garter snakes. The PRO- 

 TEROGLYPHA, with grooved teeth, perma- 

 nently erect, are poisonous. Most are 

 brightly colored. Elaps,* the coral snake; 

 Naja tripudians, the cobra of India ; N. 

 haje, Cleopatra's asp. Here belong the 

 pelagic sea snakes of the Indo-Pacific, 

 which are viviparous. 



Section IV. SOLENOGLYPHA. With the 

 maxilla reduced and serving as a socket 

 for the single large tubular tooth with 

 one or more reserve teeth (fig. 627). 

 VIPERID^, Old World, no pit between 

 nostril and eye. CROTALID.E, New World 

 and Asia, with a pit between nose and 

 eye. Crotalus* with the tail ending in 

 a rattle formed by remnants of cast skins, 

 is common throughout the United States. 

 Agliistrodon contortrix* copperhead, 

 and A. piscivorus, moccasin, lack the 

 rattle. Bothrops lanceolatus of the An- 

 tilles, possibly the most poisonous snake. 



Order VIII. Crocodilia (Loricate). 



The crocodiles, alligators, etc., 

 ome of the forms already 

 mentioned in the oval cloacal open- 

 ing with single copulatory organ, 

 immovable quadrate, and the bony 

 plates in the skin. In shape they are 

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



Coee 



FIG. 630. Ventral surface of skull 

 of crocodile. (From Wiedersheim.) 

 Cocc, occipital condyle: C/i, cho- 

 ana ; jg, jugal ; M, maxillary ; O/>, 

 basioccipital ; Or/>, orbit ; Qi, quad- 

 ; Pi, pala- 



ratojugal ; Qtt, quadrate 

 tine ; Pmx, premaxilla; 

 goid; Ts, transversum. 



ptery- 



