96 



or on the modes of connection of the zooecia. In their whole structure these forms 

 undoubtedly belong to the family Bicellariidae. The peculiar contrast in Episto- 

 mia and Synnohim^ between the proximal cylindrical and the distal widened 

 portion of the zocecium as well as the possession of pedunculate avicularia, shows 

 that the position of these genera is near to Cornucopina. In Gemellaria the distal 

 wall is as in Biigula: angulate and furnished with a series of uniporous rosette- 

 plates. We also find an angular distal wall in Didymia, the ooecia of which, like 

 those in Eiicratea and Cornucopina, are surrounded by kenozooecia, and Dimetopia 

 has like most of the Bicellariidae, free ooecia. Finally, I have been obliged to 

 set up new genera for the old F/usfra-species, Fl. nobilis, Fl. dissimilis and Fl. 

 militaris as also for Bugula Murrayana, Bicellaria Alderi and ^Catenariwi bicornis. 

 It is however with some doubt that I refer the last species to this family. 



In the following synopsis of the numerous genera of the familj% to which 

 I have been under the necessity of adding 6 more, I have as main characters in 

 the separation of the genera mainly used differences in the structure of the zooe- 

 cia themselves, as e. g. the presence or absence of an operculum, the division of the 

 zocecium in different segments by constrictions, the structure of the distal wall, 

 and next the differences in the character of the ooecia. I have used the presence 

 or absence of ooecia and avicularia, as well as the differences in the structure 

 of the avicularia, as auxiliary characters. 



Synopsis of the Genera. 



1) The colony consists of two layers, the zooecia of which are of 

 very different kinds (the zooecia in one layer are quite uncalcified, 

 without operculum, in the other laj'cr they are of the ordinary type; 

 the distal wall consists of a horizontal, basal portion with a multi- 

 porous rosette-plate, and of a frontal ascending portion; free ooecia, 

 freely movable avicularia) Dimorphozoum n. g. 



1) If the colony consists of two layers, the zooecia of the two layers 

 are of the same kind: 



2) Zooecia without operculum; (the edge of the distal wall is angu- 

 lar; within this a row of single-pored rosette-plates; free ooecia, freely 

 movable, capitate avicularia, radical fibres issue both from the frontal, 



basal and lateral aspects of the colony) . . Bugula Oken (Lev. mod.). 



2) zooecia with an operculum: 



' 111, p. 14. 



