Lia 



S. IKK DA. 



(1) Lt protects the eggs, mechanically, from external agencies. 



(2) It perhaps prevents the eggs from too much crowding. 



(3) It is made especially, as I think, fco facilitate the respiration 

 of the eggs and embryos in their early developmental 6tages. 



The first of these points is very obvious. The jelly-mass around 

 the eggs of Bufo, Rana, S al man cira, and the mass around the sepa- 

 rately deposited eggs of Triton, must all serve the same protecting 

 purpose. Small air-bubbles must act in this case as a sort of cushion, 

 and are well adapted to protect the eggs out of water. As to the second 

 point in Bufo, Baita, Halmandra, and others, in which eggs are deposited 

 in groups in water, the jelly-mass around each egg absorbs water and 

 swells up gradually, thus preventing the eggs from coming into contact 

 with one another. In the present case, the mass of eggs being deposited 

 under ground or in air out of water, the jelly can not swell up as 

 much as in other cases, and it seems probable to me that the function of 

 the air-bubbles within the jelly-mass is, in part, the means of prevent- 

 ing the eggs from too much crowding. The third point must surely 

 indicate the chief purpose of this frothy envelope. The jelly-mass in 

 this case is more liable to dry than those of the other amphibians, 

 since it is not in water. And when the outer surface of the jelly-mass 

 is dessicated and forms a crust, it effectually protects tbe inner part 

 from further evaporation ; but at the same time the inner part must 

 necessarily be excluded from the external air — a condition which would 

 cause the death of the eggs and embryos but for the presence of such 

 air-bubbles as we see in this species. 



Now comes the question : how is this peculiar frothy envelope 

 produced? It is a question to which I have given much thought and 

 attention, and the answer to which I, have tried to find out every succeed- 

 ing breeding season for some years past. All my efforts were baffled 

 until last spring, when at last I was rewarded with success. Tbe 

 breeding season was somewhat backward this year, and on the afternoon 

 of April 2(j, I found and brought home, besides some masses of eggs, 

 a pair of frogs that were together in a hollow. This pair could not 



