26 



FROGS. 



and hard, as in the wood-frog, leopard-frog, and pickerel-frog eggs, 

 which are laid earlier in the season. In the last of June and through 

 July only one other common frog is breeding; namely, the green 

 frog. The green frogs usually deposit their eg^s upon vegetation. 

 They lay on or among grass, water plants, and algae, or along grassy 

 edges of ponds, while the bullfrog almost invariably lays in brush. 

 The egg complements of the two species are also different in size. 

 The green frog seldom lays more than 3,500 or 4,000 eggs, while the 

 bullfrog may lay from 10,000 to 20,000. Usually, the egg of the 

 bullfrog has not the distinct middle envelope of jelly which is found 

 in the green frog's e^g (fig. 1, Fand D). Furthermore, this middle 

 envelope in the eggs of the green frog often is elliptical, and not round, 

 as in the eggs of the leopard and pickerel frogs (fig. 1, G and B). 

 In nature, the eggs hatch in four days or less. 



(§) 



Fig. 1.— Individual Eggs (three times natural size). 



A. Egg of common toad in two jelly envelopes or tubes, the inner of which is divided by cross 

 partitions. B. Egg of pickerel frog. Inner envelope and egg proper of same size as egg of leopard 

 frog (O) but outer envelope smaller. C. Egg of peeper. The one envelope and the egg proper to- 

 gether ajjpear the duplicate of the egg of the tree toad ( E) when it is stripped of its outer envelope. 

 D. Egg of green frog. Unlike the egg of the bullfrog, it has an inner envelope. E. Egg of tree toad. 

 The outer envelope often ragged in outline. F. Egg of bullfrog. Unlike the other four frogs, it has 

 no inner envelope. G. Egg of leopard frog. Egg proper black and white, not brown and orange as 

 in pickcral frog (B). H. Egg of wood frog. It has the largest egg proper of these eight species and 

 larger envelopes than the confusing pickerel-frog (,B) and leopard-frog (O) eggs. (After Wright, Car- 

 negie publication No. 197.) 



The eggs of the southern bullfrog are not known, and we are not 

 very familiar with its breeding habits. In Georgia, Florida, and 

 Alaoama the writer has chanced upon this species in full croaking 

 season in June and July. This species is reputed to lay small eggs 

 in large masses on or at the surface of the water in the early summer, 

 and if this be true the habits of this form are closely similar to those 

 of the northern bullfrog. 



Possible Species. — The hermit spadefoot toad is one of the 

 most erratic and transient of our toads or frogs. It suddenly appears 

 after a shower, and egg laying is soon over after an ear-splitting 

 chorus of croaking lasting a few days. Breeding usually occurs in 

 April but occasionally persists until August. This species breeds 

 in quiet pools and ponds (PI. VII, fig. 2). The eggs are enveloped 

 in a gelatinous band (PI. XVIII, fig. 4), the cross section of which 

 includes several eggs. In the common toads the eggs occur in one 



