68 BERTRAM G. SMITH 



immature specimens from 16 cm. body length upwards; in these 

 stages the spots are more conspicuous than in the larvae or the 

 older adults. In the older, full-grown specimens the general color 

 effect may vary in two ways : it may become either greenish-brown 

 or decidedly reddish brown. As stated by Reese ('03) these vari- 

 ations in color occur in both sexes. 



C. BREEDING HABITS 



1 . Breeding season 



The following data indicate the beginning of the breeding 

 season, as shown by the deposition of eggs, in northwestern 

 Pennsylvania during a series of years : 



1906 August 30 1909 August 29 



1907 September 8 1910 September 1 



1908 August 28 1911 September 4 



The summer of 1907 was an unusually 'late season' as regards 

 vegetation as well as the breeding season of Cryptobranchus. 

 This indicates the probability that climatic conditions influence 

 the time of spawning. 



Egg-laying continues for a period of about two weeks. At 

 the end of this time females have in a few instances been taken 

 with the full complement of ripe eggs still in the ovary and show- 

 ing signs of degeneration. 



The occurrence of the breeding season of Cryptobranchus in 

 the fall is in marked contrast to the habitfe of nearly all other uro- 

 deies. Some other urodeles which have a late breeding season are 

 C. japonicus, which according to several authors (Sasaki, '87; 

 Kerbert, '04; Ishikawa, '04; de Bussy '04 and '05) lays its eggs 

 during the latter part of August and the early part of September; 

 and Amphiuma, which according to McGregor ('99) breeds in 

 midsummer. Among the anura, Scaphiopus holbrookii spawns 

 during the slimmer, the time varying from June to August (Pike, 

 '86; Hargitt, '88). 



