67 



On the other hand, we have noticed that the endozocEcial ooecia in Flustra are 

 quite separated from the cavity of the zooecium by the ooecial membrane, and 

 a transference of the egg from the zooecium into the ocecium can therefore only 

 take place by the egg first leaving the zooecium through its aperture and after- 

 wards entering the ooecium on the withdrawal of the operculum of the latter. 

 As we have nowhere been able, except in the above-mentioned case, to find an 

 inner connection between the zooecium and the ooecium, we cannot doubt but 

 that the egg elsewhere always leaves the zooecium through its aperture. This is 

 undoubtedly most evident in the peristomial and the double-valved ooecia, be- 

 cause the zocecial aperture leads directly into them, and the same is the case 

 with the ooecia in Thalamoporella ; but neither can we in any other Bryozoa find 

 in the relation between the zooecium and the ooecium any difficulty for such a 

 transference. Without entering in particulars I shall here only state that in all 

 the species with ooecia, examined by me, the position of the ooecium in relation 

 to the zocecial aperture is a such that when the operculum opens to a certain 

 extent the egg will have no difficulty in reaching into the ooecium, whether the 

 transference be effected by aid of the tentacular sheath or by an independent 

 movement of the egg. Especially in the Ascophora this passage seems to be secured 

 in the best possible way as in most members of this division the zocecial oper- 

 culum in a certain position closes a space which can be looked upon as a 

 common vestibulum for the zooecium and the ocBcium, and a completely covered 

 passage is thus formed between them. Least safe the passage seems to be in the 

 family Reteporidae and the genus Exochella as there is a rather long way be- 

 tween the zocecial aperture, and the ooecium and the zocecial operculum cannot 

 close the space between the zooecium and the ocecium. 



The systematic characters in the Cheilostotnatous Bryozoa. 



While we sometimes find in the literature, as in Hincks, Waters, Jullien 

 and other writers, views concerning the larger or smaller value of different syste- 

 matic characters, the systematic importance of a single character being some- 

 times dealt with, sometimes the relative importance of several characters, yet any 

 connected or more complete review is lacking of those characters, which in the 

 present state of our knowledge might be used for systematic purposes, as also a 

 valuation of their relative importance based upon a sufficient number of examples 

 for it is only in this way, that the reader becomes able to judge in the matter. 

 We shall endeavour here to give such a review and we shall first distinguish 

 between two different categories of characters, namely the »colonial« and the »zooe- 

 cials meaning by the first those which can be referred to colonial forms and the 



5* 



