258 Eev. T. Hincks on (he 



of the zoarium. They originate from a small circular promi- 

 nence, which is always either upon or in close proximity to 

 the central stem. Two or three sometimes occur in connexion 

 with a single pair of cells. 



Family CMidoniidae. 



Chlidonia, Savigny. 



Chlidonia Cordieri^ Audouin. 



Thickly investing the stem of a seaweed. 

 Range. Australia ; Cape York ; the Canaries ; Egypt ; 

 Tyre; Bay of Tunis; Nice; Naples; coast of Calvados. 



Family Cellulariidie. 



ScRUPOCELLARiA, Van Beneden. 



Scrupocellaria Bertholletii, Audouin. 

 (PL IX. figs. 1,2.) 



Scrupocellaria Bertholletii, Savigiiy, Egypt, pi. xi. fig. 3, 

 ? Scriqjocellaria capreolus, Heller, op. cit. p. 11, pi. i. tig. 1. 



Zoarium of rather delicate habit, white and glossy, dichoto- 

 niously branched, forming small tufts. Zocecia rather long, 

 five in an internode, clavate, widest above and narrowing 

 gradually downwards ; aperture elongate-oval, with a thin 

 margin, occupying about two thirds of the front ; three spines 

 on the outer margin above, on the inner a tall spine a little 

 way down the side, and sometimes a small one above it; 

 about halfway down the cell on the inner margin an antler- 

 like scutum ^, frequently wanting, often merely bifurcate and 

 in its simplest condition acicular ; lateral aviculai'ium small, 

 placed immediately behind the three outer spines ; on the 

 front of each cell just below the aperture a large sessile ay^^it- 

 lariumj tumid towards the base, the mandibular region facing 

 towards the aperture ; mandible acute, bent at the tip, directed 

 outwards ; beak of moderate size, not abruptly bent. Vihra- 

 cidar cell wedge-shaped, narrow and bluntly pointed below, 



* Mr. Busk, following Smitt, has adopted tlie term fornix in place of 

 operculum, -which has been assigned by general consent to the oral valve. 

 At the same time he plainly indicates his preference for scutum {' Chal- 

 lenger ' Report, p. 15, footntjte), and as in framing scieutihc terminology 

 we are not bound by authority or precedent, but are free to select the 

 terms which seem to be most fitting, I shall venture to side with Mr. 

 Busk's evident preference against his practice and use the latter term, 

 which i-eems to me indubitably the better, to designate the prttective 

 appendage with which the cell is furnished in this and other species. 



