GHARIALS. 11 



it is imperfectly developed, but in certain others the greater part of 

 the tail is invested by complete bony rings — one to each vertebra — 

 and the limbs are covered with small scutes of bone (27 f)- 



One very fine specimen of the common Caiman, or Jacare-tinga 

 {Caiman sderojjs, 27), is exhibited in a table-case. 



The Gharial {Gavialis gangeticus, 5), of the rivers of northern Case i. 

 India and Aracan, and the False or Malay Gharial (Tomistoma 

 schlegeli, 6), of Malaysia, form a group of Crocodilians characterised 

 by the length and narrowness of the muzzle, and the number and 

 slenderness of the teeth. By most naturalists the group is included 

 in the same family as the Crocodiles and Alligators (with which it 

 agrees in the position of the inner aperture of the nostrils) ; but by 

 others (who regard them as the direct descendants of the long- 

 snouted Crocodilians of the Secondary period), Gharials are classed 

 in a family by themselves. In addition to the length of the muzzle, 

 Gharials are distinguished from Crocodiles and Alligators by the 

 wide separation of the nasal bones from the aperture of the nostrils, 

 and by the inclusion of the splenial bone in the long union (sym- 

 physis) between the two halves of the lower jaw. The true Gharial 

 has from 27 to 29 pairs of lower teeth, none of the latter being 

 received into pits in the upper jaw. The nasal bones are widely 

 separated from the premaxilla?. In the False Gharial, on the other 

 hand, the number of upper teeth is 20 or 21, and of lower teeth, 

 18 or 19 ; the tips of those on the sides of the lower jaw being 

 received into pits in the upper jaw. The nasal bones are in contact 

 with the premaxillfe. Gharials feed chiefly on fish, but large indi- 

 viduals of the Indian species will occasionally kill and devour human 

 beings. In England the Gharial is frequently miscalled Gavial. 



The extinct Phytosaurus (or Belodon, \), of the Triassic formation Case i. 

 of Europe, North America, and probably India, typifies a group of 

 Crocodilians (the Parasuchia), which apparently indicates a primitive 

 side-branch of this order. They are characterised by the bodies of 

 the vertebrae having slightly cupped or nearly flat terminal articular 

 surfaces ; by the nostrils being situated far back on the skull, near 

 the sockets of the eyes, and by the relatively forward position of the 

 posterior openings of the nostrils, which are situated in front of 

 the palatine bones. The armour consists of two rows of broad 

 plates on the back, and several lateral rows of smaller ones. In the 

 nearly allied Steganolepis, of the Trias of Elgin, there is armour on 

 both the upper and lower surfaces of the body. Parasuchus, from 

 the Trias of India, is a third genus. 



