FROGS. 13 



toad {H. andersonii) is bounded beneath by a white line and this by 

 a purpHsh brown or purple color. The Florida tree frog {H. gratiosa) 

 of Florida and Georgia, the largest (2^ inches long) of all our tree 

 frogs, has many roundish spots on its dorsal surfaces and very large 

 disks. The Pacific tree frog (Hyh regiUa) and the southern tree frog 

 {H. squireUa) have the thighs with no particular color pattern, are 

 not pure green on the back, like the Carolina tree frog, and have the 

 body not so slim as in this form. One occurs on the Pacific coast and 

 the other in our southern States. 



Our narrow-mouthed toads, unlike the true frogs, have no teeth in 

 the upper jaw, are never 2 inches in length, have the eardrum hidden, 

 and possess a peculiar fold of skin on the top of the head. 



CULTURE OF FROGS. 

 BREEDING HABITS. 



Those frogs which appear in the early spring usually begin croaking 

 at once and proceed to pair and ovulate with little or no intervals 

 between appearance and egg layhig, wliile those which appear last 

 wait for longer periods between emergence and croakuig and between 

 croaking and ovulation. It has been much in vogue to say of many 

 species that they breed "in early spring," but many of our forms of 

 which this has been said do not breed until summer. The males in 

 many cases resort to the breeding grounds before the females, and 

 the females may wait until their eggs are ripe before they enter the 

 water. Or, as is the case with some toads, the two may meet on the 

 trip to the water and become mated before the destination is reached. 

 The croaking or mating male seizes the fu'st female witliin reach and 

 maintains his embrace until the eggs are laid. Sometimes in gre- 

 garious species six or eight males strive for one female, and often the 

 female is killed. Fertilization comes exactly at the extrusion of the 

 eggs or slightly after it. 



At first no envelopes about the eggs are apparent and the egg 

 mass may feel soft and sticky. After a few minutes this substance 

 absorbs water, and each egg then is revealed to be a spherical body 

 closely surrounded by a membrane and by one or two jellylike 

 envelopes. (See fig. 1.) Some eggs have only the iimcr envelope 

 present. This gelatinous substance comes from the oviduct and 

 forms, when swollen, the egg capsules, tubes, bands, films, or masses 

 to wliich we are so accustomed. The egg masses (Pis. XIII to XIX) 

 are spherical in the wood frog, the pickerel frog, and in some of the 

 other true frogs; plinthlike in the leopard frog and southern leo|)ard 

 frog; a spiral in the various toads; a surface film in tlie green frog, 

 bullfrog, and tree toad; and a submerged film or mass in the swamp 

 cricket frog. In the peeper and cricket frog the eggs are separate. 

 The wood, pickerel, and leopard frogs lay their wliole complement in 

 a short time; the film form of the green frog, bullfrog, and tree frog 

 takes longer, the first two mtiintaming the same position and the 

 latter moving about during tlie process. With the toads and spade- 

 foots some time is consumed in laying their spirals or bands. In the 

 peeper several hours may transpire before the eggs are all laid. 



