l68 ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



Oviposition 



The actions of spawning in Anura are so rapid that the most rigid 

 attention is needed if some feature of the process is not to be missed. 

 The tank I have described above was made for close observations, and 

 the events showed that all its conveniences were needed. 



I began by bringing two females and seven males from a pond, and 

 putting them into the tank, filled with tap water. No spawn was laid 

 that night, nor for the next three days. I then transferred one pair to 



Fig. 43 . A pair of frogs in amplexus 



Note the defensive position of the feet of the male, posed ready to fend off 

 an attack from the rear. Note also the pectoral grip and compare with 

 Fig. 45. The female is full of eggs and has her eyes shut. Her legs are used 

 for swimming and do not have the defensive angle that the male adopts. 



another aquarium with sand on the bottom, but there was no spawn 

 after another day. Both pairs were then removed to an outdoor 

 terrarium with a pool that had been established for two years, where 

 they spawned within twenty-four hours. Although this was not 

 proof, it suggested that pond water might help to produce spawning, 

 so that I made another attempt by filling the tank with pond water, 

 and putting in it five pairs and three males. I guessed that spawning 

 might take place in the early hours of the morning, so I began observa- 

 tions at 4.00 a.m. At that hour one pair had already spawned. Nothing 

 of interest occurred until 5.45, when one of the females made a few 



