Notes on Some South African Tadpoles 63 



dependently evolved the same peculiar move of development: 

 or, on the other hand, it is possible that this mode of development 

 is actually the primitive one and the swimming tadpole stage 

 quite secondary. If the free swimming tadpole stage is actually 

 a primitive feature in frog development, as most zoologists assume, 

 it seems strange that the omission should take place in a region 

 so well watered as our forests. But the answer to this question 

 can best be derived from a detailed study of the embryology, 

 which is about to be carried out by Dr. E. Warren. 



Various other species in S. Africa depart more or less from 

 the usual course of development in frogs as exemplified in the 

 genus Rana. Boneberg's frog, originally described by the 

 writer and P. A. Methuen, from Marianhill, Natal, has a true 

 tadpole stage, but the eggs are not actually deposited in water. 

 The clusters of spawn are either attached to exposed rocks from 

 2-6 feet above the surface of the water or to the branches of 

 overhanging trees. Apparently, the eggs hatch into larvae which 

 wriggle about in the slimy mass and eventually fall into the 

 water below, or are washed therein by rains. The home of this 

 frog is bushland country in shady rivulets overgrown with 

 creepers and thorns, the water therein being actually very scanty 

 though flowing all the year round. 



Another Natal species, Megalixalus spinifrous, also lays its 

 eggs on the leaves of trees, according to Fr. P. Boneberg, and 

 a large species found in the low veld districts of the Transvaal 

 behaves in a similar way. The latter (Chiromantis xerampelina) 

 is even reported to watch over its developing young, showing 

 solicitude for their welfare most unusual amongst creatures so 

 lowly. According to information received some years ago from 

 Mrs. H. Streeter, the facts are as follows : — 



The female frog deposits a large ball of foam in which the 

 eggs are placed. This is always above a waterhole whence the 

 frog obtains water to keep the foam moist by squirting liquid 

 thereon at intervals. If the frog is killed or the water dries 

 up, the ball becomes hard on the outside like gum or glue and 

 the contents perish. It is then occupied by a large fly, apparently 



