67 



On the other hami, we have noticed that the endozooeclal ooecia in Fliistra are 

 quite separated from the cavity of the zocx^ciuni by the ooecial membrane, and 

 a transference of the egg from the zoa'cium into the ooecium can therefore only 

 take place by tiie egg iirst leaving the zoa'cium through its aperture and after- 

 wards entering the oa-cium 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 zoo^cinm and the ooecium, we cannot doui)t but 

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

 undoubtedly most evident in the pcristomial and the doul)le-valved oa'cia, be- 

 cause the zod'cial aperture leads directly into them, and the same is the case 

 with the ooecia in Tbalamoporellii; but neither can we in any other /^n/ozoo 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 ottcia, examined by me, the position of the ooecium in relation 

 to the zoo-cial aperture is a such that when the operculum opens to a certain 

 extent the egg will have no difficulty in reaching into the od'ciuni, whetber the 

 transference be etTected by aid of tbe tentacular sheath or by an independent 

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

 in the best possible way as in most members of this division the zoa>cial oper- 

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

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

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

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

 tween the zooecial aperture, and the oa-cium and the zorecial operculum cannot 

 close the space between the zooecium and the owcium. 



The systematic characters in the Cheilostomatous Bryozoa. 



While we sometimes find in the literature, as in Hi neks. Waters, JuUien 

 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 tbe reader becomes able to judge in the matter. 

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

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

 cials meaning i)y tbe first those which can be referred to colonial forms and the 



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