378 Zoological Society : — 



jpaUide brunneis : cauda unicolore hrunnea : rostro niyro, jpedi- 

 bus brunneis. 

 Lon^. tota 4*0, alee 2*0, caudse 1*2. 



Hab, Chamicurros in ripis fl. Huallaga in Peruv. Orient. {Ilaux- 

 well). 



Mus. Brit. 



Obs. Similis F. gulari (Spix, Av. Bras. ii. t. 41. f. 2) sed dorso 

 medio rubro nee cinnamomeo, et colore subtus dilutius cinereo dig- 

 noscenda. 



On the species of Crocodilus inhabiting the rivers Kwora 

 AND BiNuis (Niger and Tsadda) in Central Africa. 

 By Dr. Balfour Baikie, F.R.Geog.S. &c. 



Among the Zoological collections which I made during my visit to 

 the rivers Kwdra and Binue in 1854, were several skulls of Croco- 

 diles, varv'ing in length from 14 to 26 inches. A careful compara- 

 tive examination of these shows them all to be possessed of similar 

 characters ; but on attempting to refer them specifically, I have ex- 

 perienced considerable difficulty, their proportional measurements 

 not agreeing with any hitherto described. Two African species of 

 Crocodilus are already known, — C. vulgaris, the Nilotic or Egyptian 

 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 



