AND CROC. MARGINATUS. 483 



having observed the crania of two rare Crocodiles in the Mu- 

 seum at Belfast, the following notes regarding them have 

 been drawn up by me at the request of Mr. W. Thompson. 



I. Crococlilus cataphractus, Cuv., Oss. Fossiles, torn. v. p. 58, 

 PL V. figs. 1 and 2 ; Dum. and Bibron, Erpet., torn. iii. p. 126 ; 

 G. leptorhynchus, Bennett, Proc. Zool. Soc. 1835, p. 129 ; 

 Mecistops Bennettii and M. cataphractus, Gray's Catalog., 

 pp. 57 and 58. 



This species was founded by Cuvier upon an imperfect 

 specimen of unknown origin in the Museum, of the London 

 College of Surgeons. It was briefly described by Bennett, 

 first as a distinct species from Fernando Po, in 1835, and af- 

 terwards as a variety of G. cataphractus, in the ' Zoological 

 Proceedings ' of 1836. Mr. Gray has erected it into a separate 

 genus under the name of Mecistops, in which he includes along 

 with it the G. Journei of Bory de Saint- Vincent, and G. {Ga- 

 vialis) Schlegelii of Miiller. So far as" is known to us, no 

 representations have yet been given of the cranium divested 

 of its integuments. Plate XXXVIII. figs. 1, 2, and 3, repre- 

 sent the Belfast specimen, viewed from the top, base, and side 

 of the skull. It is evidently identical with Gray's Mecistops 

 Bennettii ; the head of the stuffed specimen of this nominal 

 species in the British Museum collection agreeing with it 

 exactly in form, and very nearly in size. The muzzle is more 

 attenuated and narrower than in C. acutus, but less so than 

 in G. Schlegelii, which constitutes the passage from the true 

 Crocodiles into the Gavials. The cranial tablet is not so wide 

 as in the Gavial, G. Schlegelii, and the crotaphite foramina 

 are proportionally smaller. The muzzle does not contract 

 abruptly in front of the orbits, but is gradually attenuated 

 from the back part of the cranium forwards. The extreme 

 width at the condyles of the lower jaw is 7 inches, behind the 

 orbits 4f inches, and in a line with their anterior border 3^ 

 inches. At the seventeenth or last tooth of the upper jaw 

 the width is 3| inches, and If in. between the eleventh and 

 twelfth teeth ; there is an expansion to 2 inches opposite the 

 ninth tooth, which is the largest in the head : thence the 

 beak contracts gradually to the space between the fourth and 

 fifth teeth, where the width is only 1 inch ; at the extremity 

 of the muzzle, between the second and third teeth, it expands 

 to If inch. The margins, when viewed in plan, are there- 

 fore more undulated and less cylindrical than in the Gavial 

 or G. Schelegelii, and there is less dilatation on the point of 

 the beak. 



The orbits are much larger than the crotaphite foramina, 

 which are separated only by a narrow interval ; while in the 

 Gavial they are large and wide apart. The lachrymals form 



1 1 2 



