REPTILIA. 
11 
are, for example, several skulls and jaws of extinct kinds 
from the Eocene of Egypt; while a large collection from the 
Pliocene Siwalik formation of India includes, among other 
interesting specimens, the snout of a colossal extinct gavial, 
RhampJiosuchus crassidens, which must have attained a length 
of about 50 feet (Wall-case 1). 
The typical modern crocodiles (Eusuchia or “ perfect 
crocodiles ”) are peculiar in having their throat so constructed 
Pig. 6. —Skull of Crocodilus palustris, a species living in Western India and 
found fossil in the Pleistocene of the Narbada Valley. 1. Right side 
view. 2. Upper view. 3. Palate. All much reduced in size. E, opening 
of median eustachian canal; N, posterior nares; 0 , orbits ; P, palato- 
pterygoid vacuities; T, supratemporal fossae ; V, basioccipital bone. 
that they can keep their mouth open under water while 
drowning prey: they are also characterised by vertebrae 
united by ball-and-socket joints. A few Upper Cretaceous 
crocodiles agree with them in these features, a skull of 
Thoracoscturus from the Greensand of New Jersey (plaster 
cast in Wall-case 3) showing the characteristic palate, while 
vertebras from the Chalk of France and the Cambridge 
Wall-cases 
1-3. 
Table-cases 
5-12. 
Wall-cases 
2a, 3. 
Table-cases 
5-7. 
