266 Miscellaneous. 



the characters of egg-cells, and passing, on the other, into the endo- 

 derinic cells. Our master, E. van Beneden, has long since made 

 analogous observations (in Campanularia dichotoma), which are 

 still unpublished. 



The free extremity of the appendicular organ terminated in a 

 hook is characterized by the development of the ectoderm, by the 

 accumulation in that tissue of corpuscles of special structure, and by 

 the considerable attenuation of the perisarc. These data may 

 perhaps serve to settle the nature of this organ. 



In the body and tentacles the intermediate lamella, which else- 

 where is amorphous, presents fasciculated fibrils, which insert 

 themselves at definite points, and which I believe to be muscular. 



A gonangium is formed by a gonotheca, a central system of canals, 

 and some gonophores. The axial canal or blastostyle spreads out 

 into a hammer-head at the upper extremity of the gonangium, and 

 furnishes laterally those caeca at the level of which the gonophores 

 are formed. In ft angulata and ft jlexuosa the latter do not 

 become either Medusas or semi-Medusas, as in the other Car.ipanu- 

 iarice ; they remain in the condition of diverticula of the wall of the 

 body, and certain of their cellular elements become ovary or testis. 



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

 fragment of a small nucleus, surrounded by a little of the proto- 

 plasm 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 corpuscle of 

 irregular form (Schron's corpuscle), 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 

 transverse 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, 0. and 

 11. Hertwig think that the sexual organs originate from the ecto- 

 derm. On the other hand, Kblliker, Hiickel, Allman, Claus, and 

 Korotneff maintain their endodermic origin. E. van Beneden sup- 

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

 tozoids 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 Eudendrium ramosurn. 



In Campamdaria angulata and C. jlexuosa the whole develop- 

 ment 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 coenosarc is constituted 

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

 ectoderm is more thickened and its cells better defined. Higher up, 

 at a certain point, the ccenosarc is inflated into a small tubercle, 

 into the interior of which penetrates a caeca! diverticulum of the 



