304. THE OCEAN WORLD. 
the head of a vulture; but the lower mandible can be opened 
much wider than a real bird’s beak. The head itself possesses con- 
siderable powers of movement, by means of a short neck. In one 
polyzoon the head itself was fixed, but the lower jaw free ; in another 
it was replaced by a triangular 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 of these polyzoa 
contain quite immature forms, yet the vulture heads attached to 
them, though small, are in every respect perfect. When the animal 
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.” 
Moreover, in Cresta, 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 inde- 
pendently 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 trans- 
mission of will in the polyzoon, though composed of thousands ot 
distinct animals, as in any individual animal. “What can be more 
remarkable,” he adds, “than to see a plant-like body producing an 
egg, capable of swimming about and choosing a proper place to 
adhere to, where it sprouts out into branches, each crowded with 
innumerable distinct animals, often of complicated organisation— 
the branches, moreover, sometimes possessing organs capable of 
movement independent of the animals !” rian 
The prey which is drawn into the vortex by the tentacles and their 
cilia enters into the mouth, to which is attached a pharynx, cesophagus, 
stomach, and intestines. In the hemal region, not far from the mouth, 
there is a special opening for the intestine. 
