260 



FALKLAND ISLANDS. 



March, 1834. 



functions they are related rather to the axis than to any of 

 the polypi. In a similar manner, the fleshy appendage at the 

 extremity of the sea-pen forms part of the zoophyte as a 

 whole, as much as the roots of a tree do of the whole and 

 not of the individual buds. Without doubt this is a very 

 curious variation in the structure of a zoophyte : for the 

 growing part in most other cases does not manifest the least 

 irritabihty or power of movement. 



I will mention one other kind of structure quite as ano- 

 malous. A small and elegant Crisia is furnished, at the 

 corner of each cell, with a long and slightly-curved bristle, 

 which is fixed at the lower end by a joint. It terminates in 

 the finest point, and has its outer or convex side serrated 

 with delicate teeth or notches. Having placed a small piece 

 of a branch under the microscope, I was exceedingly surprised 

 to see it suddenly start from the field of vision by the move- 

 ment of these bristles, which acted as oars. Irritation gene- 

 rally produced this motion, but not always. When the 

 coralline was laid flat on that side from which the toothed 

 bristles projected, they were necessarily all pressed together 

 and entangled. This scarcely ever failed to excite a consi- 

 derable movement among them, and evidently with the object 

 of freeing themselves. In a small piece, which was taken out 

 of water and placed on blotting-paper, the movement of these 

 organs was clearly visible for a few seconds by the naked 

 eye. 



In the case of the vulture-heads, as well as in that of the 

 bristles, all that were on one side of a branch, moved some- 

 times coinstantaneously, sometimes in regular order one after 

 the other ; at other times the organs on both sides the branch 

 moved together ; but generally all were independent of each 

 other, and entirely so of the polypi. In the Crisia, if the 

 bristles were excited to move by irritation in any one branch, 

 generally the whole zoophyte was affected. In the instance 

 where the branch started from the simultaneous movement 

 of these appendages, we see as perfect a transmission of will 

 as in a single animal. The case, indeed, is not different from 



