OF SELBORNE. 61 



LETTEE XVII. 



TO THOMAS PENNANT, ESQUIRE. 



SELBORNE, June 18, 1768. 



Wednesday last arrived your agreeable 

 letter of June the 10th. It gives me great 

 satisfaction to find that you pursue these 

 studies still with such vigour, and are in 

 such forwardness with regard . to reptiles 

 and fishes. 



The reptiles, few as they are, I am not acquainted with, 

 so well as I could wish, with regard to their natural history. 

 There is a degree of dubiousness and obscurity attending 

 the propagation of this class of animals, something analogous 

 to that of the Cryptogamia in the sexual system of plants ; 

 and the case is the same with regard to some of the fishes ; 

 as the eel, &C. 1 



The method in which toads procreate and bring forth 

 seems to be very much in the dark. Some authors say that 

 they are viviparous ; and yet Ray classes them among his 

 oviparous animals ; 2 and is silent with regard to the manner 

 of their bringing forth. Perhaps they may be sVw plv worcxot, 

 ^co <TE COOTOXO, as is known to be the case with the viper. 



The copulation of frogs (or at least the appearance of it 

 for Swammerdam proves that the male has no penis intrans) 

 is notorious to everybody ; because we see them sticking 

 upon each others' backs for a month together in the spring 

 and yet I never saw or read of toads being observed in the 

 same situation. 3 



1 Since this observation was published it has been demonstrated by 

 Mr. Yarrell that eels deposit their spawn like other fishes. ED. 



2 Toads are oviparous. ED. 



3 In this respect toads do not differ from frogs. ED. 



