3 74 



understanding, one may compare my 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 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 to 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 temporaria 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 5000 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 during seven hours, suffered 

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

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

 mer it falls into the 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 still the even- 

 ings 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 species 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 

 without the supply of food necessary for preserving the energies of 

 the vital functions *. Dr. A. Smith himself was an eye-witness how 

 several specimens of Brachymerus fasciatus were found in a lethargic 

 state in a hole of a tree, completely closed, conspicuously open before 

 and grown together afterwards. Such a tenacity of life is never to 

 be observed in a Snake : the higher the temperature the greater is 

 the need of food ; and a Snake having endured fasting during six or 

 nine months always dies. Moreover, the tenacity of life in the Ba- 

 tracbians is proved by their power of reproduction, which never has 



* Cf. " Observations on the Common Toad, and on its long abstinence from 

 food," by John Brown, Esq. (Ann. & Mag. Nat. Hist. 1842, vol. x. p. 180). 



