OF SELBORNE. 
01 
LETTER XYII. 
TO THOMAS TENNAXT, ESQUIllE. 
Selbor^e, June 18, 17G8. 
N Wednesday last arrived your agreeable 
letter of June tlie 10th. It gives me great 
satisfaction to find tliat you pursue these 
studies still vrith 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.^ 
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 and is silent with regard to the manner 
of their bringing forth. Perhaps they may be eVw woToxoi, 
l^cooroKoi, 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.^ 
^ 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. 
^ In this respect toads do not differ from frogs. — Ed. 
