HVBRIDIZATION OF XENOPUS 



1025 



within a year after the hatching of the eggs. Laboratory-bred toads are somewhat 

 smaller than the wild-type but not conspicuously so. 



Female XI 1 may often exceed 100 mm. in body length and weigh about 

 75 gms., while the maies may attain 80 mm. and an average weight of 45 gms... 

 Laboratory-bred individuals rarely reach thèse proportions and females longer 

 than 93 mm. are exceptional. It may be noted that we maintain our colony at 

 22° C, feeding the tadpoles with nettle (Urtica) powder and the post-meta- 

 morphic stages with chopped liver. 



The dorsal pattern of both species is a dark green with patches of black or 

 rown. In Xll it is subject to a fair degree of variation but is quite uniform in 

 lp. However, the ventral surface is a clear distinguishing character. Whereas in 

 ïll it is usually white or a pale cream in colour and either immaculate or finely 

 ppled in grey, in Xlp the ground colour is a bright orange and heavily blotched 

 thickly stippled in a violaceous black (figs. 1-5). 



FlG. I. 



Dorsal pattern of X.l. peter si ?. 

 Length 77 mm. The pattern is typical of the subspecies. 



exelopment of XI 1 and Xlp 



The embryology of both toads is as described in the " Normal Table of 

 nopus laevis " (Nieuwkoop and Faber 1956) except for the variations for 

 lp commented on below. 



