84 BERTRAM G. SMITH 



is not always successful in dislodging the adult. In cases where 

 the rock is lifted and overturned, the water is discolored and the 

 hellbender, aided by its protective coloration and the swift 

 current, may escape. When seen, however, it may usually be 

 captured. A record kept for six years ('06-' 11) shows that from 

 twenty-nine nests containing eggs a male was captured in ten 

 cases, a female never. 



The duration of the brooding habit has not been definitely 

 determined, and perhaps varies greatly. In different nests in which 

 a male was present, eggs were found in various stages of develop- 

 ment up to about three weeks old; unfortunately I was obliged 

 to discontinue field work at a date varying from two to four we^ks 

 after the beginning of the breeding season. In no case where the 

 eggs were in an advanced stage of development can it be recorded 

 that the male had been continuously present, or even that he was 

 the same male that fertilized the eggs; but the entire absence 

 of females from nests containing eggs is significant. 



With regard to the origin of this paternal brooding instinct 

 two suggestions (Smith, '07) were made: (a) the brooding instinct 

 may have originated in connection with the feeding habit ; or (b) 

 in holding the nest the male may be primarily concerned in await- 

 ing the coming of another ripe female. Both views assumed that 

 in Cryptobranchus we have an example of the brooding habit in an 

 incipient state. Further observations indicate that the brooding 

 habit is well estabhshed and manifested as a distinct impulse 

 from the moment of fertilization; its origin is thus thrown back 

 into the remote past, and concerning it we can only speculate. 



The evidence for the first interpretation may be briefly stated 

 as follows : Both sexes are voracious eaters of the newly-laid eggs ; 

 during the spawning season the majority of the adults taken have 

 the stomach filled with eggs. There is evidence that the females, 

 when opportunity is afforded, gorge themselves with eggs more 

 freely than the males. The number of eggs found in the stomach 

 of a single adult usually ranges from fifteen to twenty-five, a 

 number sometimes greatly exceeded in the stomachs of spent 

 females. In one case, in which the body of a spent female ap- 

 peared greatly swollen, the stomach was found to be greatly dis- 



