OBSERVATIONS ON THYONE BRIAREUS. 269 



The two short ventral tentacles are most active and constantly 

 move in and out of the mouth opening, while the larger tentacles 

 wave about more slowly. The latter are moved through the 

 water or scraped over the bottom and then consecutively wiped 

 off in the mouth. When one of these large tentacles is wiped off, 

 its proximal end is pushed into the mouth first and the distal 

 branches follow. Before one tentacle has emerged, another is 

 usually being pressed down upon it ready to enter. Sometimes 

 two of the large tentacles bend toward the mouth at once but in 

 no case were two seen to enter the mouth simultaneously, one of 

 them always bending back after a moment to make way for the 

 other. The eight large tentacles are used in a more or less regu- 

 lar sequence, and in general it may be said that the one which 

 has been out of the mouth longest and which is farthest from the 

 tentacle which is emerging will be the next to enter the mouth. 

 They are seldom used in the exact order one would expect from 

 this statement however. For example, those nearest the muddy 

 bottom are usually more frequently used than the others. 

 Many observations were made as to the sequence in the wiping of 



Fig. 3. Diagram to show the arrangement of the tentacles around the mouth as 

 seen in an anterior view. 



the tentacles and the follow^ing series is a typical one (see Fig. 

 3) : 2, 7, I, 4, 10, 8, 3, 9 ; 7, 2, I, 4, 10, 8, 3, 9 ; 2, 7, i, 4, 

 10, 8, 3, 9 ; 7, 2, 4, h 7, 10, 3, 4, 8 ; 2, 7, 9, i, 3, 9, 7, i, 8, 3, 

 10, 2, 8, I, 7, 4, 8, 3, 10, 2. In this series a rather regular se- 



