ON THE DERMAL ARMOUR OF JACARE AND CAIMAN 29 
their hands belonged either to C. diporcatus or C. palustr’s. On the 
other hand, all the skulls of crocodiles from Asia which I have met 
with (amounting to at least twenty) are either those of C. dzporcatus 
or of the species which I have called domdbtfrons; so that I suspect 
the latter title will turn out to be a synonym of palustris, 
6. Crocodilus rhombifer. 
I have not been able to obtain any skull of this species, which, 
according to Cuvier’s account and figures (‘Oss. Fossiles, t. ix. 
p. 102), resembles C. Americanus in the great convexity of its nasal 
region, but differs from it in the greater breadth of the skull, and in 
the strong converging preorbital ridges, which appear to be limited 
to the lachrymal bones. If the figures are to be trusted, however,. 
there are other very important distinctive characters about the cranium 
of this species ; for Cuvier’s, fig. 2, pl. 331, which gives a view of 
the palate, shows the premaxillo-maxillary suture forming a nearly 
straight transverse line. 
There remain several species of Crocodilus whose skulls I have: 
not been able to examine, and of which no sufficient descriptions 
exist. Of these, (7.) C. galeatus and (8.) C. Gravesii ( planirostris, would 
appear to be very distinct forms. (9.) C. marginatus is considered by 
Dumeéril and Bibron to be only a variety of C. vulgaris; and they 
take the same view of (10.) Crocodilus suchus. Professor Owen, how- 
ever, has figured the cranium of an Egyptian mummy under this 
name (‘Monograph on the Reptilia of the London Clay,’ Pal. Soc. 
1850). In the under-view of this skull (tab. i. fig. 2), the junction of 
the premaxilla and the maxilla in the palate seems to be broken 
away; but on the left side, the palatine process of the maxilla is 
entire, as far as the level of the anterior margin of the sixth tooth, 
and there is not a trace of a suture behind this point. Are there, 
then, two or more species of Crocodile in Egypt, as Geoffroy St.- 
Hilaire supposed ? 
With regard to the distribution of the species of Crocodilus, C. 
vulgaris, C. marginatus, and C. suchus(?) appear to be exclusively 
African ; all the crocodiles from other parts of the Eastern hemisphere, 
which I have met with, belong, as I have stated above, either to 
C. biporcatus or C. bombifrons, both of which species are found in the 
Ganges. Crocodilus galeatus appears to be peculiar to Siam. Croco- 
dilus Americanus and C. rhombtfer are undoubtedly American. C. 
Journet has been supposed to be African ; but such positive evidence 
