CROCODILUS. 19 
CROCODILUS. 
Crocodilus, auct. 
1. Grocodilus americanus, Schneid. 
The American Crocodile has a most extensive geographical distribution. It is found 
in the large West-Indian Islands, and is very common on the Atlantic side of Mexico and 
Central America*; on the Pacific side it extends southwards to Ecuador, whence 
specimens were brought by Mr. Fraser. Naturally, a species of so wide a range 
exhibits no inconsiderable amount of variation, especially in the comparative length of the 
snout, in the more or less regular arrangement of the lateral dorsal scutes, in the promi- 
nence of the keels of the scutes, and in the development (as regards number and size) of 
the scutes protecting the neck. The last of these characters is the least trustworthy of 
all, and therefore I am not prepared to admit the species named Crocodilus mexicanus by 
Bocourt. ‘Lhe variations in the width of the skull are all the more perplexing, as evi- 
dently a great change takes place in this respect during the growth of the individual. 
From specimens less than one foot in length little information is to be gained, but as they 
grow the snout is more produced and becomes comparatively narrow. This goes on until 
they have attained a length of five or six feet. About that period the growth of bone is 
slower in the longitudinal axis of the jaw than in the transverse, and the jaws increase in 
width as the animal becomes older. It is therefore necessary in the utilization of this 
character to compare specimens of the same size and presumably of the same age. 
Induced by the labours of the French naturalists who distinguished several species of 
the Central-American Crocodile, I re-examined a very large series (34 specimens), and 
came to the conclusion that at least two forms, a long-snouted anda broad-snouted, could 
be distinguished, although even these two forms cannot be sharply defined, all having, 
besides, one important character in common by which the American Crocodile can always 
be recognized, namely, the longitudinal elevation of bone along the fronto-nasal region. 
For the long-snouted form the subspecific term of acutus, and for the broad-snouted 
that of moreletii + may be chosen, and it may be useful to indicate in the accompanying 
table the amount of variation which attains in each of these two forms. 
* Wyman (Sill. Journ. vol. 49, 1870, p. 105) records the occurrence of Crocodilus acutus on the coast of 
Florida, and describes a skull 18} inches long, comparing it with one of similar size from South America. As 
the Floridan skull is much narrower than any I have examined of C. acutus, and resembles in this respect the 
Crocodile of the Orinoco, I have some hesitation in referring the Floridan Crocodile to C. acutus. 
+ Wiegmann, Herpetol. Mex. p. 22, and Strauch, Syn. Crocodil. p. 41, maintain that Crocodilus rhombifer is 
common in Mexico and other parts of Central America. This statement rests evidently on a confusion of the 
Cuban species with the proad-snouted form of C. americanus. As far as I have been able to ascertain, the 
CO. rhombifer of Cuba is peculiar to that island. It lacks the longitudinal rise of the fronto-nasal region, and 
the dorsal scutes form four regular longitudinal series besides one or two irregular lateral rows. Duméril’s 
statement as to the shortness of the web between the outer hind toes in Cuban specimens, I am unable to confirm ; 
this membrane shrinks in dry specimens, but in our Cuban Crocodiles it is as much developed as in C. acutus, 
or nearly so. Finally, I may remark that the skull on which Cuvier founded C, rhombifer may prove to be 
nothing but a short-snouted C. americanus. 
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