Crocodiles. 5 



compressed teeth in distinct sockets, which are continually being Crocodilia. 

 renewed fi-oni helow. The sknll is relatively large in proportion "Wall-case, 

 to the body, and is usually much depressed ; its component bones ' ' 

 are firmly united and generally have a characteristic sculpture ^^^ ^9*^to 13 

 on their external surface. The palatines and pterygoids unite in 

 the middle line and thus close the palate, and very frequently one 

 or both of these paired bones develop inferior plates, which meet 

 beneath the narial passages. The quadrate is tightly wedged in 



Fig. 6. — Crocodihis pahislris (Lesson). 1, lateriil, and 2, upper views of skull; 3, palatal 

 view of cranium; E, aperture of median eustachian canal; N, posterior nares; 

 0, 0, orbits ; P, P, palato-pterygoid vacuities; 2', supra-temporal fossae; V, basi- 

 occipital. The figures are much reduced. Common, living in Western India. 

 Fossil in the Pleistocene deposits of the Narbada Valley, India. 



among the adjacent bones ; the tympanic cavities usually com- 

 m.unicate with the mouth by three eustachian canals ; tho 

 mandibular symphysis unites by suture ; there are, as a rule, no 

 ossifications in the sclei-otic of the eyeball. There is almost 

 invariably a lateral vacuity in the mandible. The vertebrae 

 of these reptiles are cup-shaped or concave at both ends, 

 as in Teleosaurus ; or concave in front and convex behind, as in 

 the Crocodile from Sheppey (Fig. 7) and in all living Croco- 



