256 CASWELL GRAVE 



CONCLUSIONS 



The observations of the tadpole larva of Amaroueium recorded 

 in this paper show: 



1. That the body of the tadpole as it is propelled through the 

 water by the tail, is in constant clockwise rotation on its long 

 axis, the rotation being caused either as a consequence of the 

 asymmetrical form of the body or by a torsion of the tail during 

 its strokes or by a combination of both. 



2. That tadpoles show a definite positive response to light for 

 a very brief interval immediately following their liberation from 

 the parent colony, but react negatively to light during the 

 latter and greater part of the free-swimming period. 



3. That tadpoles invariably remain at or near the upper 

 surface of the water during the first part of their free-swimming 

 period, but, as the time for metamorphosis approaches, descend 

 into the lower strata of water and swim at or near to the bottom. 

 This behavior has been interpreted to indicate responses to 

 gravity, negative at first, positive finally. The positive response 

 to gravity is exhibited in varying degrees of definiteness, not at 

 all in a small per cent of tadpoles. Its expression seems to be 

 aided by, but not entirely conditioned upon, the presence of 

 directive rays of light. 



4. That the viscid contents of the glandular ends of the adhe- 

 sive papillae are extruded upon the outer surface of the tunic 

 toward the close of the free-swimming period and that the 

 initial attachment of the tadpole takes place when one or more 

 of these protruding viscid droplets comes (accidentally) into 

 contact with the surface of a foreign body. 



5. That the free-swimming period of the tadpole varies in 

 duration from ten minutes to two hours. 



