232 Zoological Society :— 



quence he could not bring, in a more or less accordant correspondence 

 with a certain province of the earth's surface, those genera which are 

 really peculiar to such a separated district. And although that 

 sketch, with which the first volume of Schlegel's 'Essai ' is concluded, 

 deserves the more admiration, as this branch of science, not pre- 

 viously cultivated, was raised by him at once to a degree of phi- 

 losophical view adequate to his system, it must share the destiny 

 of every such attempt, when our knowledge of faunas as well as 

 of geography is more advanced : many stated truths will hold good 

 — a part or all the principles applied before will form the basis 

 of the next attempt ; but many other points will appear to be modi- 

 fied or wrong, and will be replaced by other results. For a better 

 understanding, one may compare ray view of the geographical dis- 

 tribution of Reptiles in Africa with that of Schlegel. In this at- 

 tempt I have maintained his idea of species, but I think I have 

 gained more general and more true results by more limited genera 

 (far different from those " subgenera," which are in fact species) 

 and by a modified view of the geographical regions. But we now 

 also want far more correct information concerning the genera and 

 families, before we can arrive at very satisfactory conclusions. 



There is, in the first place, a much greater disproportion in the 

 distribution of Reptiles over the different regions, with respect to the 

 number of genera and species, as well as of individuals. Amphi- 

 bian life is entirely different from that of the higher animals, being 

 exposed to the slightest modifications of external physical influ- 

 ences ; and there are again great differences among the Reptiles 

 themselves. Let us compare some of our Snakes with Batra- 

 chians, in a few instances only. Frogs and Toads are found on the 

 Shetlands, whilst Vipera bents, the most northern Snake, is already 

 scarce in the north of Scotland. Rana temper aria is met with in 

 the Alps round lakes, near the region of eternal snow, which are 

 nine months covered with ice ; whilst Vipera berus reaches only to 

 the height of oOOO feet in the Alps, and of 7000 in the Pyrenees. 

 A Triton or a Frog being frozen in water will awake to its former 

 life, if the water is gradually thawed ; I found myself that even the 

 eggs of Rana temporaria, frozen in ice for seven hours, suffered 

 no harm by it, and were afterwards developed. A Snake can only 

 endure a much less degree of cold : even in the cold nights of sum- 

 mer it falls into a state of lethargy ; it awakes late in the spring, 

 when some Frogs and Tritons have already finished their propaga- 

 tion ; it retires early into its recess in harvest, while the evenings 

 still resound with the vigorous croaking of the Tree-frogs and the 

 bell-like clamour of Alytes obstetricans. Our European Snakes die 

 generally, in captivity, during the winter, partly from want of food, 

 partly by the cold nights. The eggs of our oviparous s})ecies are 

 deposited during the hottest part of the year, requiring a high tem- 

 perature for development. Further, though some accounts of Ba- 

 trachians enclosed in cavities of the earth or trees may be exag- 

 gerated, the fact is stated by men whose knowledge and truth are 

 beyond all doubt, that such animals live many years apparently 



