CONCERNING EGGS 67 



responsible for their production, these being oval 

 in form, and possessing a tough leathery shell. 

 They are laid one at a time, but owing to their 

 being coated with a sticky secretion, ultimately 

 adhere together into a mass. 



In the case of frogs and toads, the eggs of the 

 females are frequently produced in clusters and held 

 together by a jelly-like substance ; but at other 

 times only a single one is laid, which is of large size 

 and also enveloped in a gelatinous covering. Mr. 

 E. G. Boulenger gives the following figures in 

 reference to the number of eggs laid by some of 

 the best-known species of frogs and toads : * Green 

 toad about 11,000, edible frog about 10,000, common 

 toad about 6,000, natterjack about 3,500, common 

 frog about 3,000, agile frog about 1,000, green-tree 

 frog about 900. . . .' 



The ova of the common frog and toad are easily 

 distinguished the one from the other inasmuch as 

 those of the former are deposited in large masses 

 which may be seen floating upon the surface of 

 the water in ponds, brooks, and ditches during the 

 months of January, February, and March (according 

 to locality and climatic conditions) ; while those of 

 the latter are laid in long gelatinous strings, which 

 are entwined around water plants, and remain 

 submerged. 



The spawning habits of a species of tree-frog 

 found in tropical America are very remarkable, 

 the females depositing their eggs and enfolding 

 them between the leaves of trees which overhang 

 ponds, leaving but a small opening at the lower 



