376 MR. LISTER ON THE STRUCTURE AND FUNCTIONS 



channel of communication with the ovary. Rudiments of arms were at first scarcely 

 discernible, but gradually grew more distinct. In an hour or two the mouth opened, 

 and the imprisoned particles rushed out with the vivacity and rapid motions of 

 bees swarming {h A). Their action could not at all be referred to currents in the 

 water, and was very different from the dancing of inorganic molecules ; such, indeed, 

 that it was' difficult not to believe them possessed of vitality. They darted about 

 in all directions, some sweeping off at once, some flying to a distance and returning 

 as quickly, others traversing hastily the surface of the polypus, and all by degrees 

 dispersed in the surrounding water. The mouth closed slowly ; agitation continued 

 in those particles that remained within ; after a while it opened again, and more 

 escaped, and thus in about an hour the cavity became nearly emptied of them and 

 filled with clear water: a soft substance occupied its bottom (h 5). The mouth 

 continued to open and close slowly at intervals : the arms, which were about 

 twelve in number, lengthened, and the bag contracted. This action of the mouth, 

 slow motions of the arms, and slight inflection of the pedicle, were the only signs 

 of vitality in the young polypi. Afterwards, to my surprise, they gradually shrunk 

 away ; and 1 found that though their internal communication with the ovary 

 seemed cut off till some time after they had discharged their particles, agitation 

 subsequently began in the substance at the bottom of the bag ; and currents at 

 long intervals succeeded, between it and the top of the ovary, which continually 

 subtracted matter from the young polypus. The latter became more rugose, and at 

 length was altogether absorbed. Thus h 6 gives the appearance of the same ovary when 

 the fifth ovum was about to emerge ; of the first there remained but a doubtful 

 vestige ; the second had diminished by degrees to a small knob ; the third was fast 

 dwindling, and the fourth was emptied of particles. The cord, with its side attach- 

 ments to the ovary (see c 2), continues till the last ovum is gone ; when it is itself ab- 

 sorbed, leaving the shell empty. Apparently the disappearance of every young polypus 

 was caused in the manner described. In no instance could I discover one to be de- 

 tached, as I entertained no doubt that they would have been if left in their natural 

 situation in the sea, and thus my hopes of tracing their further economy were disap- 

 pointed. 



A small Campanularia, which was thought to be in an early stage of its existence, 

 Plate X. fig. 2, grew on a cell of the Sertularia pluma : it consisted only of a 

 knob or bulb by which it was fixed, a simple stem, and one cell containing a po- 

 lypus. The usual currents alternated every few minutes between the stomach and 

 the bulb, the fluid continuing longest in the latter, and the greatest agitation of the 

 particles being there. It remained mostly expanded for two days, during which no 

 growth or material change took place in it. 



The annular strictures along the stem of the Coryne, Plate X. fig. 3, and the 

 shape of its small cell, gave to this zoophyte a sort of resemblance to Campanularia. 

 The stem seemed capable of a slight motion, and the head and arms were constantly 



