HABITS OF CRYPTOBRANCHUS ALLEGHENIENSIS. 



31 



In its natural environment the hatching of the embryo is per- 

 haps delayed a little by the slightly lower temperature, but the 

 climatic conditions are such that it seems at least certain that 

 hatching occurs at some time during the fall. 



According to Kerbert ('04), the eggs of C.japonicus, kept at 

 an average temperature of 13 C, hatched in from 52 to 68 days, 



Fig. 8. Embryos of Cryptobranchus allegheniensis, ready to hatch, about six weeks 

 old. Natural size. 



and at the time of hatching the embryos were 30 mm. long. 

 Since the extreme length of the adult C. japonicus is 159 cm. 

 (Gadow, '01) as compared with 56 cm. for C. allegheniensis, there 

 is far from being a corresponding difference in the size of the 

 embryos at the time of hatching. 



