370 



ZOOLOGY 



SECT. 



far the greater number being natives of tropical and temperate 

 zones. The Sea-turtles, including the Hawk's-bills and the Luths, 

 are for the most part, but not entirely, confined to the tropical 

 seas. Giant Land-tortoises occur, or occurred in historic times, on 

 islands of the Galapagos and Mascarene groups. 



Of the Crocodilia the Caimans are confined to Central and 

 South America. The Alligators are represented in North America 

 by one species and in China by another. The true Crocodiles occur 



Fig lOlU,— Skull uf Beiodon. A, from tibove ; B, from below. A, orbit ; BOt basioucipital ; C/i, 

 internal narca ; D, prc-orbital fossa ; i'xo. cxoccipital ; I'r. frontal ; Ju. jugal ; La. lacrymal ; 

 jyij:. maxilla ; n. external narcs ; Na, nasal ; Pa. parietal ; PL palatine ; Pmx, premaxilla ; 

 For. post-orbital ; Prf. prefrontal ; Ft. pterygoid ; Qu. quadrate ; S, lateral temporal fossa ; 

 6', superior temporal fossa ; &i. squamosal ; Vo. vomer. (From iSittel.) 



widely distributed over Africa, Southern Asia, the northern parts 

 of Australia and tropical America, while the Gavial occurs only in 

 certain Indian and Burmese rivers. 



Geological Distribution. — The Squamata are geologically the 

 most recent of tlie existing orders of Reptiles. The earliest fossil 

 remains of Lizards have been found in beds belonging to the 

 Jurassic and Ci'etaceous periods ; but most of the families are not 

 I'epresented earlier than the Tertiary. All the known fossil-re- 

 mains of Snakes, except one imperfectly known form from the 



