AMPHIBIA 201 



change color quickly from dark brown to a delicate graJ^ In the 

 dajd;ime they hide quietly in sheltered crevices of bark or the crotches 

 of limbs, but at night they become lively and noisy, jumping about 

 and busily catching insects. They breed in shallow pools in May, 

 passing through a regular tadpole stage, and metamorphose into 

 small perfect frogs in aljout seven weeks. 



Hylafaber, a native of Brazil, is one of the most interesting of the 

 tree-frogs, on account of its remarkable voice and extraordinary nest- 

 building habits. Its voice is said to resemble that of a mallet beaten 

 against a copper plate. When caught it utters a cry like that of a 

 wounded cat. It makes an aquarium-like nest for its eggs and young, 

 by digging a basin of some depth in the bottom of shallow pools and 

 building a mud wall about it. The 

 whole inside of the basin is most 

 carefully smoothed off by rubbing 

 the belly over it. The male takes 

 no part in this building opera- . 

 tion, but raises an unearthly 

 racket all the while. ~^ 



Hvla amldii (Fi"- 116) is re- ^^'^- H^.— ff///a giddii xl. Female 

 a V - \ a- I -^'iVa eggs in incipient dorsal brood- 



markable on account of the fact pouch. (From Gadow.) 

 that the female carries the eggs 



on the back in a shallow depression till they are almost ready 

 for metamorphosis. 



The genus Nototrerna (Fig. 115, B) differs from HyJa in that the 

 female has an egg pouch or marsupium on the back, which is merely 

 a fold of the skin. It has been suggested that the marsupium may be 

 a specialization of the simple pocket seen in Hyla gceldii. 



The tiny Acris gryllus (Fig. 115, C), or "Cricket Frog" of eaistern 

 and central United States, is one of our smallest frogs. It is described 

 as a merry little frog, chirping constantly even in captivity. It fre- 

 quents the borders of pools, jumping into the water if disturbed and 

 quickly burying itself in the mud at the bottom. 



Family 5. Cystignathidce is another of the large anuran families, 

 having like the Hylidae about 150 species. They play about the 

 same role in the southern continents (Notogaea) as the Ranidse 

 do in the northern continents (Arctogsea). Some of them are 

 difficult to distinguish from the Ranidas. The whole family is 

 ill-defined, being specialized in a great many directions. They 



