Chapter I: The Biology of the Crocodilia

CLASSIFICATION

As in most groups of animals, there is considerable difference of opinion as to the proper classification of the Crocodilia.

One of the older textbooks (Claus and Sedgwick) divides the order Crocodilia into three sub-orders: the _Teleosauria_, _Steneosauria_, and _Procœlia_, the last only being represented by living forms. The Procœlia or Crocodilia proper are divided into three families,--the _Crocodilidæ_, the _Alligatoridæ_ (including the caiman as well as the alligator), and the _Gavialidæ_.

This division into families seems to be based mainly on the shape of the head, or, at any rate, it throws those forms together that have heads of the same outline.

It is this outline of the head that Ditmars (_Reptiles of the World_) uses in classifying the Crocodilia, which, he says, are all included in the single family--_Crocodilidæ_. The following list, taken from his _Reptiles of the World_ (pp. 68-69), will give a clear idea of the number, distribution, and maximum size of the members of the order Crocodilia. More will be said of some of the members of this list later.

---------------------------------------------+----------------+-------
| _Habitat_ | _Max.
| | Size_
---------------------------------------------+----------------+-------
A. Snout extremely long and slender, | |
extending from the head like the handle of a | |
frying pan | |
_Gavialis gangeticus_, Indian Gavial |Northern India |30 ft.
_Tomistoma schlegeli_, Malayan Gavial |Borneo and |
|Sumatra |15 ft.
| |
B. Snout very sharp and slender; of | |
triangular outline | |
_Crocodilus cataphractus_, Sharp-nosed | |
Crocodile |W. Africa |12 ft.
_Crocodilus johnstoni_, Australian Crocodile |Australia |6-8 ft.
_Crocodilus intermedius_, Orinoco Crocodile |Venezuela |12 ft.
| |
C. Snout moderately sharp; outline distinctly| |
triangular | |
_Crocodilus americanus_, American Crocodile |Fla.; Mexico; |
|Central and S. |
|America |14 ft.
_Crocodilus siamensis_, Siamese Crocodile |Siam; Java |7 ft.
_Crocodilus niloticus_, Nile Crocodile |Africa generally|16 ft.
_Crocodilus porosus_, Salt-water Crocodile |India and |
|Malasia |20 ft.
| |
D. Snout more oval; bluntly triangular | |
_Crocodilus robustus_, Madagascar Crocodile |Madagascar |30 ft.
_Crocodilus rhombiferus_, Cuban Crocodile |Cuba only |7 ft.
_Crocodilus moreletti_, Guatemala Crocodile |Guatemala; |
|Honduras |7 ft.
| |
E. Snout short and broad; conformation | |
barely suggesting a triangular outline | |
_Crocodilus palustris_, Swamp Crocodile |India and |
|Malasia |12 ft.
_Osteolæmus tetrapis_, Broad-nosed Crocodile |W. Africa |6 ft.
| |
D′. Outline of head similar to that of | |