SIWALIK CROCODILIA, LACERTILIA, AND OPHIDIA. 
11—219 
Distinctness and affinities . — With the exception of a slight variation in the 
position of the niaxillo-premaxillary suture in one example, the preceding specimens 
show that the characters of the type cranium of the Perim Island Siwalik crocodile 
are constant ones, while the comparisons already instituted indicate the specific 
distinctness of this form both from C. 'palustris and 0. sivalensis. From 0. siamensis 
the Perim crocodile is readily distinguished by the deeper facial sculpture, and the 
relatively narrower interorbital bar ; and as it presents no resemblance to C. porosus, 
and therefore presumably none to C. pondicherianus, and does not approach any other 
species as closely as it does the C. palustris group, its right to specific distinction 
appears evident, and Falconer’s name may accordingly be retained. 
That G. palceindicus is a member of the C. palustris group is perfectly evident ; 
but the peculiar facial profile appears to indicate that it is an aberrant form which 
diverged at a comparatively early period from the type stock; as in the case of 
0. sivalensis, the more backward position of the maxillo-premaxillary suture on the 
palate indicates a species somewhat less differentiated from other existing crocodiles 
than is G. palustris. 
Distribution. — Remains of this species have been hitherto recognized only from 
the Siwaliks of Perim Island. 
Grenus II. Ghaeialis, Geoffrey.^ 
Syn. Leptorhynchus, Clift. ^ 
Definition . — As already mentioned,^ it appears not improbable that the so-called 
Holops from the upper cretaceous of N. America may be included in the present 
genus in the sense in which that term is here employed. With the probability of 
that inclusion the genus may be provisionally defined as follows, vis .'. — Skull 
elongated into a rostrum, teeth numerous in the existing species), nasals 
separated by a long interval from the prernaxillse, 1st and 4th mandibular teeth 
biting into notches in the cranium (1st notch roofed over in Q. pachyrhynchus), upper 
and lower teeth interlocking, splenial entering into mandibular symphysis, facial 
profile curved in front of orbit. The extremity of the rostrum is frequently 
expanded, the anterior border of the orbit may be prominent or not, and interdental 
pits may or may not be present in the maxilla for the reception of the tips of the 
mandibular teeth. An additional upper tooth between the proper first and second 
is usually present. 
Number of species. — The genus is represented at the present day solely by the 
Indian O. gangeticus ; in which the teeth number the mandibular symphysis 
( 25 “ 26 ) 
extends to the twenty-third or twenty-fourth tooth, the anterior border of the orbit is 
prominent, most of the lateral teeth are directed obliquely, and those of the lower 
jaw are not received into pits in the maxilla. 
1 ‘Mem. d. Museum,’ vol. XII. p. 97 (1825). Amended from Gmialis. 
2 ‘Trans. Geol. Soc.’ ser. 3. vol. II pt. 3. p. 375 (1828). 3 Vide supra, page 211. 
