INTRODUCTION 193 



posing the animal to fire ; from a single specimen sufficient 

 venom is collected for the poisoning of about fifty arrows. 

 Although Batrachians, as well as Reptiles, differ from 

 Mammals and Birds in the absence of hairs or feathers, 

 hair-like appendages on the body and thighs are present 

 in profusion in the recently discovered frog Trichobatrachus, 



W./'. 





Fig II. — The Hairy Frog {Trichobatrachus robustus). 



[After Boulengcr.) 



of Africa. Sense-organs, similar to what is known as the 

 lateral line in Fishes, are present on the sides of the head 

 and along the body in many of the Urodeles, in all tad- 

 poles, and in the aquatic frog Xenopus. As in Reptiles, 

 Batrachians frequently change their " skin," the thin, 

 transparent outer layer of the epidermis, which first 

 becomes detached at the angle of the mouth, being turned 



