APPENDIX. 377 



lodged the seta when in a state of rest. In most species 

 the seta is serrated with distant teeth on one side. 



Where there are more than two rows of cells, the 

 marginal cells differ in conformation from the central. 



As in Scrupocellaria, the opening of the cell is sometimes 

 protected by a pedunculate operculum. The genus, there- 

 fore, may, like that, admit of being divided into sections, 

 distinguished respectively by the presence or absence of a 

 pedunculate operculum. 



a. Operculatae. 



1. C. rudis, n. sp, 



Multiserial ; opening of cells oval, margin much thick- 

 ened, with a strong projecting upturned spine on each 

 side in the central cells, and with three strong and long 

 similar spines on the outer side, and a smaller one on the 

 inner side in the marginal cells. Operculum spatulate, 

 or pointed above, entire. Each cell of the central rows 

 with two small avicularia in front, immediately below the 

 mouth. Each marginal cell with a single large vibraculum 

 hx front below the mouth. Vibracula slender, very trans- 

 parent. Setae short, not serrated. 



Hab. — Bass Strait. 



Colour dirty white : forms a broad frondose polyzoarium 

 1| to 2 inches, or perhaps more, in height. The branches, 

 all disposed in the same plane, are flat, thick, and about 

 \i\i of an inch wide, composed of from four to sis rows of 

 comparatively small cells, which viewed behind appear 

 lozenge or diamond shaped, and arranged quincunicaUy. 

 It is not always easy to observe with accuracy the outHne 

 of the vibracula, owing to the extreme tenuity of their 

 walls, but the groove along the upper border is very dis- 

 tinct and most usually has the seta lying in it. The 

 avicularia on the marginal cells are very large, but not 

 uniform in size. Along eaeh border of the branches 

 runs a bundle of radical tubes, the number of which dimi- 



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