382 HISTORY OF BRITISH ZOOPHYTES. 



be ascertained even with the naked eye. By the aid of a 

 lens, however, the nature of the change is much more evi- 

 dent. You then see that the branches are tubes, inhabited 

 by living creatures ; that long bud is a cell, the dwelling- 

 place of a polype ; that there may be above a hundred of 

 these clustered together; and that as one stone may have 

 several distinct villages planted upon it, the whole popula- 

 tion of a district of six square inches may be upwards of a 

 thousand. The first symptoms of life that the observer 

 perceives is the polype, which had shrunk out of sight on 

 being disturbed, pushing forward to the mouth of the cell, 

 as if to reconnoitre. If all is quiet, you will soon see the 

 polype, in the form of a little white rod, protrude from 

 the cell in a horizontal direction. This rod is composed of 

 a bundle of tentacula, amounting to about fifty. The next 

 change that takes place is the unfolding of the tentacula ; 

 not in the star-like form assumed by the Hydra, but in the 

 form of two horse-shoes, the one enclosing the other. The 

 outer and larger horse-shoe is spread out like a lady's ivory 

 fan. The inner range is unfolded in the same manner, but 

 it is of smaller dimensions. There is something remarkably 

 elegant in this form of the polype; and though it is the 

 more usual aspect, it is not the only one. There is another 



