84 BICELLARIID.E. 



ences of character. As in B. flabellata, there are almost 

 always three spines at the outer angle of the aperture, 

 along the edge of the segments. 



I confess that I rank this beautiful form as a distinct 

 species with some hesitation. It may be a question 

 whether, in the face of its essential agreement with B. 

 flabellata in all the leading structural points, the differences 

 which it undoubtedly exhibits should be regarded as more 

 than varietal. In the absence, however, of intermediate 

 forms it seems right to give it a separate name. 



Viewed with reference to B. flabellata, B. calathus is a 

 dwarf form of simple habit, in which the less luxuriant 

 development of the zoarium is accompanied by an increase 

 in the size of the individual elements of the structure 

 (cell, avicularium, &c.). 



In the dried state the two are at once distinguishable by 

 the difference in colour. 



BUGULA PLUMOSA, Pallas. 



Plate XII. figs. 1-5. 



SOFT-FEATHERED CORALLINE, Ellis, Corall. 33, no. 1, pi. rviii. fig. a, A. 



? SERTULARIA FASTIGIATA, Linn. Syst. ed. 12, 1314. 



Ci.i.u I.AKIA PLUMOSA, Pallas, Blench. 66: Couch, Corn. Faun. iii. 128, 



pi. xxiii. fig. 4. 



CELLARIA PLUMOSA, Ellis $ Sol. Zooph. 21. 



CRISIA PLUMOSA, Lamx. Bull. Soc. Phil. 1812, iii. 185 ; Pol. coral, flex. 62. 

 CRISIA FASTIGIATA, Templeton, Ann. N. H. ser. 1, ix. 468. 

 BICELLARIA PLUMOSA, Blainv. Actinol. 459. 

 < 'MM I.AKIA PLUMOSA, Gray, B.M. Oat. Had. 111. 

 BUOULA PLUMOSA, Busk, B.M. Cat. i. 45, pi. liv. figs. 1-5 : Alder, Supp. 



North. Cat., Trans. Tynes. Nat. F. 0. T. (20 eep.) : Better, 



Bryoz. d. Adriat. Meeres, 15. 



Zoarium consisting of slender, feathery, confervoid tufts ; 

 branches flabellate, dichotomously divided into narrow 

 linear segments, disposed spirally round the central 



