MANUAL OF NATURAL HISTORY. 71 



slender, sub-cylindrical ; teeth nearly equal ; 

 feet webbed. Old World. 



2. FAMILY. Crocodiles (Crocodilidse). Body fusi- 



form ; muzzle oblong, depressed ; teeth un- 

 equal; lower canines fit into notches in edge of 

 upper jaw ; feet webbed. Old World chiefly. 



3. FAMILY Alligators (Alligatoridae). Muzzle 



broad, obtuse ; teeth unequal ; lower canines 

 fit into a pit in edge of upper jaw; feet 

 scarcely webbed. New World. 



III. ORDER. AMPHISB^ENIA^S (Amphisbsenia). 



Body elongate, cylindrical, naked, with square 

 imbedded plates in cross rings ; tail short, conti- 

 nuous, blunt ; tongue flat, not sheathed, nicked ; 

 eyes small, hidden ; eyelids none ; ears hidden ; 

 mouth small ; jaws not extensile ; feet none, or 

 rarely in front ; skull very solid ; vent rather trans- 

 versely plaited. 



1. FAMILY. Trigonophes (Trigonophidae). Teeth 



on edge of jaws, nearly united at base, un- 

 equal, conical, rather compressed ; nostrils 

 lateral, small, oval ; prseanal pores none ; limbs 

 none. 



2. FAMILY. Double - Walkers (Amphisbsenidse). 



Teeth on inner side of jaws, conical, simple, 

 pointed ; nostrils lateral, small ; nape with a 

 longitudinal groove ; limbs none ; prseanal 

 pores distinct ; tail short. 



3. FAMILY. Lepidosternons (Lepidosternidse). 



Teeth on inner side of jaws, conical, simple, 



