SAURIA. 181 



animals to deviate suddenly from their course; consequently it is easy to 

 escape from them by pursuing a zig-zag direction, or by running round them. 



Their eggs are as large and hard as those of a Goose; the females keep 

 careful watch over them, and tenderly protect their young for some months. 

 They inhabit fresh water, are extremely ferocious and carnivorous, cannot 

 swallow under water, but drown their prey, and place it in some submerged 

 crevice of a rock, where they allow it to putrefy before they eat it. 



The species, which are more numerous than they were thought to be 

 previous to my observations, are referable to three distinct subgenera, viz. 

 GAVIALS, true CROCODILES, and ALLIGATORS. To the latter belongs 



Croc, lucius, Cuv. It inhabits the southern parts of North America, for- 

 ces itself into the mud in severe winters, and remains torpid. The female 

 deposits her eggs in alternate layers with beds of earth. 



FAMILY II. 



LACERTINIDA.(1) 



This family is distinguished by the tongne, which is thin, extensi- 

 ble, and terminates in two threads, like that of the Coluber and 

 Viper; the body is elongated; the gait rapid; each foot has five toes 

 separate and unequal, the hind ones particularly so, all armed with 

 nails; the scales on the belly and round the tail are arranged in 

 transverse and parallel bands; the tympanum is level with the head, 

 or but slightly sunk and membranous. A production of the skin 

 with a longitudinal slit which is closed by a sphincter, protects the 

 eye, under whose anterior angle is the vestige of a third eye-lid; the 

 false ribs do not form a complete circle. 



The species being very numerous and various, we subdivide them 

 into two great genera. 



MONITOR. 



This genus contains species of the largest size; they have two teeth in both 

 jaws, but none in the palate; the greater number are recognized by their 

 laterally compressed tail, which renders them more aquatic. The vicinity 

 of water sometimes brings them in the neighbourhood of Crocodiles and 

 Alligators, and it is said that by whistling they give notice of the approach 

 of these dangerous animals. This report is most probably the origin of the 

 term Sauvegarde or Monitor applied to some of their species, but the fact is 

 very uncertain. 



Lac. nilotica, L. Strong conical teeth, the posterior of which become 



(1) Lacerta, a Lizard. 



