49 



Crocodile, and C. marginatus of Southern Africa. Of these, accord- 

 ing to the best recent authority, namely Dr. Gray, the characters 

 are, — . 



C. vulgaris. — "Head elongate, triangular, flat, smoothish above, 

 narrow, tapering at the sides, nearly twice as long as the width of 

 the head behind ; muzzle at the notch nearly two-thirds the width 

 of the forehead, at the ninth tooth as wide as half the distance be- 

 tween the eyes and nostrils ; forehead flat, with nearly parallel sides." 



C. marginatus. — " Head elongate, triangular, rather convex, 

 rounded, sides slightly swollen behind the notch, half as long again 

 as the width of the head behind ; muzzle at the first notch as wide 

 as the forehead, and at the ninth tooth as wide as two-thirds the 

 distance between the eyes and nostrils ; forehead deeply concave, with 

 the sides high, prominent and nearly parallel ; dorsal plates* very 

 strongly keeled." 



I shall now describe generally the skulls which I brought home, 

 giving the measurements of four of them ; from which it will be 

 seen, that while in various prominent points they more resemble the 

 latter, yet in proportional measurements they approach more nearly 

 to, while not altogether agreeing with, C. vulgaris, thus showing that 

 in many characters they are intermediate, and thus either lowering 

 these two into mere varieties, or what is, I believe, more probable, 

 establishing for themselves specific characters. 



" Head elongate, oblong, somewhat triangular, rather convex, espe- 

 cially posteriorly, rounded, upper surface rough, sides distinctly 

 swollen behind the notch ; length more than twice the width of head 

 behind ; forehead slightly concave, sides not prominent, converging 

 anteriorly ; muzzle at notch nearly two-thirds the greatest width of 

 forehead ; at the ninth tooth more than two-thirds the distance be- 

 tween the eye and nostrils." 



Measurements. 



No. 1. No. 2. No. 3. No. 4. 



in. in. in. in. 



Extreme length 26 24 j- 22-i- 21 



Greatest width behind 12f 12 llj. 10^ 



Distance from eye to nostril. . 10-f- 10 9 8f 



Breadth at ninth tooth 7-f 6\ 6i 5f 



Breadth at notch 4£ 3f 3f 2f 



Width of forehead, anteriorly. 5 4\ 4± 4 



"Width of forehead, posteriorly 6-±- 5f h\ 5 



Extreme length of lower jaw .. 29 27 24^- — 



The proportions of all these correspond almost exactly, and I have 

 ascertained the proportional measurements of a smaller one to be the 

 same, although from its being in pieces and not yet put together, I 

 have not time to take the exact dimensions. They show the Croco- 

 dile from the Binue to be proportionally longer than C. vulgaris, and 

 much more so than C. marginatus, to be in form of upper surface 

 and of forehead near the latter, but without the prominent sides to 



No. CCCXXX. — Proceedings of the Zoological Society. 



