1862.] OF CROCODILE FROM WEST AFRICA. 217 
raised line or carina. In C. leptorhynchus, those in the neighbour- 
hood of the four larger scuta bear a projecting oblong umbo; and 
C. frontatus has this developed in a manner still more marked. 
The same character prevails in the rest of the scuta. In all three 
species there are six rows of large scuta down the back, varying in 
width, diminishing to four rows in the lumbar region. In C. vulgaris 
these scuta are flat, with only a slightly raised longitudinal line or 
earina. In C. leptorhynchus this carina is much more raised, so as to 
form regular crests. In C. frontatus some of them have an oblong 
umbo, others a crest, and others only a raised line: the affinity in 
this respect is greater with C. leptorhynchus than C. vulgaris. It is 
the same with regard to the crest down the tail. In all three the 
rows of dorsal scuta down the back become only four in number 
after passing the hind legs, forming four raised lines, two on each 
side of the spine; the inner crests or lines on each side then gra- 
dually approximate (in C. vulgaris forming a narrow channel) and 
thin off and become obliterated. The outer crest on eachside, at 
about the seventh or eighth joint behind the hind legs, becomes 
broader and spreads out into a flat plate or leaf turned out horizon- 
tally on each side. There are about seven joints in which this flat 
table-shaped position of the scuta occurs, and about the same number 
prevails in all three. As this disposition, however, does not com- 
mence suddenly at any particular joint, but proceeds by gradations 
out of the crest on the back, the number may be modified according 
to the degree at which the observer reckons the horizontal leaf to 
commence. The size of these scuta is proportionally larger in C. 
frontatus and C. leptorhynchus than in C. vulgaris. These hori- 
zontal thin scuta extend one on each side for a certain distance ; and 
then all at once the double row ceases, and is replaced by a series of 
single erect scuta running down the top of the tail. In my specimens 
the number of joints before this single crest commences, reckoning 
from immediately behind the hind legs, is as follows :— 
(OTT SOG SRE GORGE a Smid tortan ds 18 
C. leptorhynchus ........-. Sane Swine eae we 
PARAS ats g 50212 244. wubsieh shal elatale sts < 13 
And the number of erect terminal joints is— 
CTOULG ESE co late oes je = mise aden 
C. leptorhynchus .........- ets Vem satetey ote 19 
CPPONTAEUS oe «ate ws Oe «tre tebe. «x LD 
The colouring of C. frontatus is much nearer that of C. lepto- 
rhynchus than C. vulgaris. The latter is coloured pale ashy brown, 
blotched irregularly with dark brown. The other two have the dark 
blotches distributed in transverse bands,—C. frontatus having every 
alternate two rows of transverse scuta pale and dark—a disposition 
followed in C. leptorhynchus, but not so regularly. 
Total length of my specimen, 21 inches; total length of head, 
from tip of snout to back of under jaw, 33 inches ; breadth of head, 
12 inch; length of muzzle to front of eye, 14 inch; length of eye, 
