212 SIDNEV F. HARMEE. 



that several are produced in each fertile internodej apparently 

 by a modification of cells of the funicular tissue, and that their 

 further development depends on their entering into definite 

 relation with a polypide-bud. If this association is brought 

 about, it may be assumed that what might at first have de- 

 veloped into a zooecium becomes an ovicell. In abnormal 

 cases, where several polypide-buds enter into relation with 

 ova, two or more ovicells may be produced in the same inter- 

 node (17^ p. 166; pi. xii, fig. 13). It may further be sup- 

 posed that the failure to bring about the association between 

 the egg and the polypide-bud results in such abnormalities as 

 that shown in fig. 12 of my former paper, and that this or some 

 other cause, such as the failure to get fertilised, results in the 

 development of the empty ovicells which are so frequently 

 observed. 



On decalcifying a number of ovicells, it is soon noticed that 

 many ovicells are either completely empty or are abnormally 

 developed. An ovicell, with complete tubular aperture, may 

 be absolutely devoid of any trace of primary or secondary 

 embryos. In some cases, these empty ovicells are probably 

 the result of degeneration which has set in after the comple- 

 tion of the process of development of free larvae. After the 

 escape of the last larvae, the remaining tissues of the ovicells 

 degenerate, and are gradually absorbed. Many of my sections 

 bear out this assertion. 



In other cases, however, the degeneration takes place in 

 ovicells which have produced no larva?. Empty ovicells which 

 are near the growing-points are, probably, generally of this 

 character. It is easy to obtain evidence of the fact that, in 

 such cases, degeneration may set in at various periods — some- 

 times after the egg has developed to a considerable extent. 

 In some cases, this may be the result of the absence of fertili- 

 sation — a process of which I have vainly endeavoured to prove 

 the existence. That fertilisation does actually occur at some 

 period can hardly be doubted, considering the fact that normal 

 spermatozoa are developed in some colonies. In other cases, 

 the degeneration is probably due to the atrophy of the poly- 



