252 AMPHIBIOUS SAURIANS. 
consistent plan in the economy of animated 
nature, under which each individual, whilst 
following its own instinct, and pursuing its 
own good, is instrumental in promoting the 
general welfare of the whole family of its co- 
temporaries. 
Cuvier observes, that the presence of Croco- 
dilean reptiles, which are usually inhabitants of 
fresh water, in various beds, loaded with the 
remains of other reptiles and shells that are 
decidedly marine, and the further fact of their 
being, in many cases, accompanied by fresh- 
water Tortoises, shows that there must have 
existed dry land, watered by rivers, in the early 
periods when these strata were deposited, and 
long before the formation of the lacustrine ter- 
tiary strata of the neighbourhood of Paris.* 
The living species of the Crocodile family are 
twelve in number, namely, one Gavial, eight 
true Crocodiles, and three Alligators. There are 
also many fossil species: no less than six of 
these have been made out by Cuvier, and several 
* M. GeofFroy St. Hilaire has arranged the fossil Saurians 
with long and narrow beaks, like that of the Gavial, under the 
two new genera, Teleosaurus and Steneosaurus. In the Teleo- 
saurus, (PI. 25'. Fig. 2.) the nostrils form almost a vertical 
section of the anterior extremity of the beak; in the Steneo- 
saurus, (PI. 25', Fig. 3.) this anterior termination of the nasal 
canal had nearly the same arrangement as in the Gavial, opening 
upwards, and being almost semi-circular on each side. — Recher- 
ches sur les grands Sauriens, 1831. 
