742 



THE AMERICAN NATURALIST [Vol. XLIII 



JNon-iertUe eggs 10 per cent. 



Drying up of ponds . 25 per cent. 



Insects, newts, fish, etc 39 per cent. 



Fungi 1 per cent. 



Disease 5 per cent. 



Total "85 per "cent." 



The remaining 15 per cent, may meet the following fate : 



Drying up 20 per cent. = 3 per 100 eggs. 



Reptiles 6 per cent. = .9 per 100 eggs. 



Boys 2 per cent. = .3 per 100 eggs. 



Sewers, wells, etc 15 per cent. = 2.25 per 100 eggs. 



Winter 25 per cent. = 3.75 per 100 eggs. 



disease 3 per cent. = .45 per 100 eggs. 



Miscellaneous ( itu-huH,,,, old one) .. 9 per cent. = 1.25 per 100 eggs. 



SUMMAEY 



B. I. americanus spawns from the latter part of April to 

 the first of July. 



This species lays in small ponds and only a portion of 

 each is used as a spawning ground. 



The males are the first to reach the water in the spring. 



88.8 per cent, of all the toads in a pond at any given 

 time are males. Males are in proportion to females as 

 80.7:100. 



Trilling in the full vigorous voice is heard only during 

 the mating season. 



Females respond to the call of the males. 



Males will not hold other males. 



Spawn may be deposited at a depth of eighteen inches 

 or more. This depth does not affect materially the hatch- 

 ing. 



Fertilization takes place in an improvised basket formed 

 by the hind feet of the male and the body and hind legs of 

 the female. 



85 per cent, of the eggs laid in natural ponds are fertile. 

 Oviposition requires six to eighteen hours. 

 The laying of two or four strands of eggs at a time can 

 not be considered of specific importance. 



