lyO ECOLOGY AND LIFE HISTORY OF THE COMMON FROG 



eggs there, even though this spot was a very small fraction of the 

 available space. This behaviour is often found in the ponds. The recoil 

 of the issuing eggs caused the pair to glide into view as I was watching 



Fig. 45. A View of a Pair as Seen in the Lower Mirror of the Tank 



Note that the fingers of the male touch or overlap, and that the arms 

 completely encircle the female, well forward of the main mass of eggs in the 

 body of the female, and so able to do httle to expel the eggs by pressure. 

 In this pair, the feet of the two frogs are in contact. Each of the two long 

 toes on the right of the picture belongs to a different frog. 



the lower mirror, and it was the position of the arms of the female that 

 drew my attention to the fact that she was spawning. 



Sperm Emission Stimulus 



It is essential in the Anura that the emission of sperm should occur 

 at the same moment as the expulsion of the eggs, for fertihzation is 

 only possible for a short time afterwards, probably because, as explained 

 in Chapter i, precipitation of the outer globulin layer is so rapid. In 



