442 



ANIMAL LIFE-HISTORIES 



what as in the form last described. Details are wanting, but the 

 young are said to hatch out as tadpoles. 



In some other cases there is a more or less well-developed 

 pouch for the reception of the eggs on the upper surface of the 

 mother's body. In a small Brazilian tree-frog {^Hyla Goeldii), for 

 example, the skin grows out into a narrow fold surrounding an 

 oval area in which the eggs are placed, presenting an appearance 

 suggestive of a shallow dish full of pale-coloured oranges. There 

 is a large quantity of food-yolk, and the young have almost 



attained the form of 

 the adult at the time 

 they hatch out. In 

 the pouched tree - 

 frogs [JVototrema) of 

 tropical South Ame- 

 rica the female pos- 

 sesses a permanent 

 pouch on the upper 

 side of her body, 

 with an opening at 

 the back. The young 

 sometimes begin their 

 free existence as ad- 

 vanced tadpoles, but 

 in most of the species 

 they have acquired 

 the adult form before they make their way out of the pouch. 



Limbless Amphibians (Gymnophiona ). — The life -histories 

 of these curious burrowing snake-like creatures have not been 

 very exhaustively studied, but there are considerable differences 

 between those species which have so far been the subject of in- 

 vestigation. One of the Cascilians {Ichthyophis glutinosa, fig. 967) 

 native to South and South-east Asia is one of the least aberrant 

 species as regards development. The female excavates a hole in 

 damp earth close to a stream, and lays some two dozen large eoo-s, 

 round which she coils her body during their development. Shortly 

 before hatching, the tadpole stage within the &'g<g possesses three 

 pair of long plume-like external gills of scarlet colour, and a pair 

 of gill-clefts. There is also a small tail-fin. The gills are lost 

 before the larva emerges, when it at once makes its way into the 



-Female of Surinam Toad [Pipa Americana)^ carrying the 

 developing young on her back 



