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AMPHIBIA 



(2) C. b. a. In a Brazilian tree-frog, Hyla goeldii, it is the 

 female which takes charge of the eggs, carrying them on the 

 back. How they get there is still unknown, but we may 

 surmise that they are placed by the male. The whole surface 

 of the back is occupied by one layer of twenty-six large 

 yellow eggs, four millimetres in diameter, on which, in the 

 specimen described, the embryos, coiled round the enormous 

 vitelline sphere, can be distinguished with the naked eye. 

 The skin of the back is extended into a narrow fold which 

 borders and supports the egg-mass on the sides, thus suggesting 

 an incipient stage of the dorsal pouch to be described here- 

 after in the allied genus Nototrema. (Fig. 15.) The embryos 



Fig. 15. — Hyla goeldii, a tree-frog carrying eggs on its back : a, from 

 above ; b, from the side ; c, young when hatched. 



are much elongate in shape, colourless, with a large flat head, 

 in which the eyes are distinguishable as two black points ; no 

 traces of gills are to be seen. The young leaves the egg in 

 the perfect state, but still provided with a longish tail. 



An allied, but larger, species from British Guiana, Hyla 

 evansii, has adopted the same mode of nursing. The eggs, 

 twenty-two in number, measure eight or nine millimetres in 

 diameter. 



A frog of the family Hemiphractidae, Ceratohyla bubalus, an 

 inhabitant of the Andes of Ecuador, Bolivia, and Peru, also 

 carries its eggs on the back. A female specimen, measuring 

 sixty-three millimetres from snout to vent, has been obtained 

 in Peru, carrying nine large spherical eggs, ten millimetres in 

 diameter, each containing a little frog distinctly visible 



