ON THE DERMAL ARMOUR OF JACARE AND CAIMAN 301 
The posterior teeth of the upper jaw, and almost all those of the lower 
jaw, are received into'interdental pits; the orbital margins are not 
raised ; and the premaxille are hardly at all expanded. The 
premaxillo-maxillary suture does not reach the third tooth behind 
the notch. 
I propose the name Rihyxchosuchus to indicate that generic type 
which is at present represented by the solitary species called by 
Miller and Schlegel Crocodilus (Gavialis) Schlegelii, and admirably 
described and figured by them in their essay, ‘Over de Krokodilen 
van der Indischen Archipel,’ in the ‘ Verhandelingen over de natuur- 
lijke Gesch. der Neder]. overzee. Bezittingen, 1839-1844. Under the 
title Crocodilus (Gavialis) Schlegelit (p. 18), they say—“ The Gavial 
from Borneo, when compared with the Indian one, is principally dis- 
tinguished by the following characters :— 
“1, By its stronger form and better developed limbs. 
“2, By its much less slender head and snout, which last does not 
narrow so suddenly in front of the eyes as in G. Gangeticus. 
“3. By the smaller number of teeth, of which there are twenty 
above and eighteen below on each side, while G. Gangeticus has 
= or ; furthermore, the teeth are stouter, less curved, and less sharp, 
and are disposed more perpendicularly, and the ninth tooth of the 
upper jaw (reckoning from the front) is considerably larger and 
stronger than the others ; whence it follows that, just as in the true 
Crocodiles, the snout at the level of this tooth exhibits a lateral 
projection. 
“4. By the shorter symphysis of the under jaw. 
“5. By the absence of the swollen nasal prominence (neusklep), 
which characterizes the Gangetic Gavial. 
“6, By the less expanded form of the tabular upper surface of the 
hinder part of the skull. 
“7, By the very slight production of the edges of the orbit. 
“8. By the large eyes. 
“9g, By the presence of a number of small nuchal shields, while 
G. Gangeticus has but one pair. 
“10, By the strongly developed keels of the dorsal scutes. 
“ 1, By the much larger scales on the under parts and on the 
legs of the animal. 
“ 2, By the different colours with which it is variegated.” 
These authors further point out that the vomers appear for a small 
space in the posterior part of the palate, that the opercular or splenial 
bones join in the symphysis of the lower jaw, and that the cervical 
