BREEDING HABITS OF DESMOGNATHUS FUSCA. 17 



of the eggs, and in her assumption of the very unusual attitude 

 during this period, we have an interesting example of a perfectly 

 automatic response to external conditions. Otherwise her atti- 

 tude would hardly have shown, as it did, so exact a correspond- 

 ence to the aberrant one previously assumed by their own 

 mother, but would rather have been the characteristic one which 

 the foster mother had taken in brooding her own eggs. The 

 chief of the conditions controlling this automatic response would 

 seem to have been the presence of the eggs themselves, since, 

 after the foster mother had once reached the pool, she apparently 

 did not return to the stone again but was always found in or near 

 the pool. The peculiar position and orientation of the bodies 

 of the two females while successively brooding this particular 

 batch of eggs is most satisfactorily explained, however, as a 

 response to some unusual conditions in the surroundings of the 

 nest, such as the possible entrance of a little light into the nest 

 from one direction. This explanation receives some corrobora- 

 tion in the fact that a little crevice was noted leading from the 

 surface into the side of the nest toward which the head of the 

 adult was directed. Furthermore, the newly hatched larvae, 

 which would be expected to be negatively phototropic if they 

 are to succeed in reaching the neighboring water by working their 

 way down through the moist earth and debris, oriented them- 

 selves in the direction opposite to that of the mother. 



It is moreover possible that we have a further automatic 

 response exhibited by the mother in seeking the water after 

 the young had hatched. This movement toward the water 

 would be of use to the offspring, for they tend to cling to the 

 mother and would thus be eventually guided by her to the water. 

 Under natural outdoor conditions where the nest would be 

 farther away from the water than was possible within the limited 

 dimensions of the terrarium, the time occupied in making this 

 transfer might roughly coincide with the duration of the terres- 

 trial larval stage. 



That the terrestrial larval stage is really a definite one is 

 shown by the behavior of the newly hatched larvae when placed 

 in the water. They are so well developed muscularly that they 

 can not only swim, but can maintain a horizontal position in the 



