136 



THE OCEAN WORLD. 





real bird's beak. The head itself possesses considerable powers 

 of movement, by means of a short neck. In one zoophyte the head 



itself was fixed, but the 

 lower jaw free ; in another 

 it was replaced by a tri- 

 angular hood, with a 

 beautifully - fitted trap- 

 door, which evidently 

 answered to the lower 

 mandible. In the greater 

 number of species each 

 cell was provided with 

 one head, but in others 

 each cell had two. 



"The young cells at 

 the end of the branches 



Fig. 59. Corpuscles from which Fig. 60. First form of the 



originate the Polypidom. Polypidom. (Lacaze-Duthiers.) O f these COralHneS Contain 



quite immature polypi, yet the vulture heads attached to them, 

 though small, are in every respect perfect. When the polypus was 

 removed by a needle from any of the cells, these organs did not appear 

 to be in the least affected. When one of the vulture-like heads was 

 cut off from a cell, the lower mandible retained its power of opening 

 and closing. Perhaps the most singular part of their structure is, 

 that when there are more than two rows of cells on a branch, the 

 central cells were furnished with these appendages of only one-fourth 

 the size of the outside ones. Their movements varied according to 

 the species ; but in some I never saw the least motion, while others, 

 with the lower mandible generally wide open, oscillated backwards and 

 forwards at the rate of about five seconds each turn ; others moved 

 rapidly and by starts. When touched with a needle, the beak generally 

 seized the point so firmly that the whole branch might be shaken." 



In the Cresia, Darwin observed that each cell was furnished with 

 a long-toothed bristle, which had the power of moving very quickly ; 

 each bristle and each vulture-like head moving quite independently of 

 each other ; sometimes all on one side, sometimes those on one branch 

 only moving simultaneously, sometimes one after the other. In these 

 actions we apparently behold as perfect a transmission of will in the 

 zoophyte, though composed of thousands of distinct polyps, as in any 



