460 EECOKD OF CUREENT RESEARCHES RELATING TO 



The spermatozoicls seem to be formed by a small nucleus, or 

 fragment of a small nucleus, surrounded by a little of the protoplasm 

 of the mother -cell, of which the rest serves to form the tail. 



The female gonophore contains only one ovum, the germinal 

 vesicle of which, when not fecundated, is analogous to that described 

 by W. Flemming, E. van Beneden, Kleinenberg, O. Hertwig, and 

 Bergh, in various animals. It contains a small clear corj)uscle of 

 irregular form (Schron's corpuscle)j from which start from three to 

 six filaments which appear to terminate at the inner surface of the 

 germinal spot ; carmine colours it strongly. Segmentation by trans- 

 verse furrows of unilateral direction produces a ciliated planula, 

 showing a cellular ectoderm and an endoderm. 



Four opinions are current as to the origin of the sexual organs : 

 Huxley, Keferstein and Ehlers, Claus, Kleinenberg, Schulze, and 

 0. and E. Hertwig, think that the sexual organs originate from the 

 ectoderm. On the other hand, Kolliker, Haeckel, Allman, Claus, and 

 Korotneif, maintain their endodermic origin. E. van Beneden sup- 

 ports a third opinion, namely, the ectodermic origin of the spermato- 

 zoids-and the endodermic origin of the ova. Van Koch and Bergh 

 confirmed Van Beneden's views. Lastly, Ciamician has maintained 

 the ectodermic origin of the ova and the endodermic origin of the 

 spermatozoids in Endendrium ramosum. 



In Campanularia angulata and C. fiexuosa the whole development 

 of the sexual organs may be traced by studying a gonangium from its 

 base of insertion to its apex. 



In the pedicle of the male gonangium, the ccEnosarc is constituted 

 as in the stolons and the branches ; but at one or two points the ecto- 

 derm is more thickened and it^ cells better defined. Higher up, at a 

 certain point, the coenosarc is inflated into a small tubercle, into the 

 interior of which penetrates a coecal diverticulum of the central cavity, 

 bounded by a few endodermic cells. Beyond the latter we see the 

 intermediate lamella, then some well individualized ectodermic cells, 

 larger than the others (these are the mother-cells of the testis) ; and 

 finally the whole is covered by the ordinary ectodermic cells. In the 

 cavity of the gonangium, at its base, are young g(mophores, in which 

 we find, from within outwards, a diverticulum of the cavity of the 

 blastostyle, epithelial endodermic cells, the intermediate lamella, a 

 small cellular mass of a horseshoe shape, originating from a few 

 difierentiated ectodermic cells, and, lastly, a layer of ectodermic cells. 

 The little mass is the young testicular tissue. The different gono- 

 phores have the same constitution, with the exception of the develop- 

 ment of the tissue, which gradually acquires a larger and larger 

 volume. In the uppermost gonophores all the elements which sur- 

 round the mature testis are in process of atrophy. The conclusion is 

 tbat the spermatozoids originate from the ectoderm. 



In the pedicle of a female gonangium we find at the base one or 

 two large endodermic cells projecting into the gastrovascular cavity, 

 having a large nucleus and no vibratile flagellum, in fact, presenting 

 all the characters of young ova of the gonophores. At the upper 

 extremity of the pedicle we see one or two differentiated endodermic 



