12 Mr. H. J. Carter on new /Species o/" Hydractiniidge. 



Ceratella sjnnosa, n. sp. 



Zoophyte procumbent, thickly branched, hard, flexible, of a 

 dark rich red-purple colour. Main branches round, brownish, 

 covered with small, smooth, often subspatulate, erect spines. 

 Stem dividing subdichotomously into purple branchlets, which 

 terminate in abruptly pointed extremities. Hydrothecse the 

 same as in the foregoing species ; most prominent over the 

 round branchlets, to which they give, en projil, a serrated, 

 somewhat Sertularian, appearance, tlie teeth of which are in- 

 clined forwards. Minute structure : main stems composed of 

 clathrate chitinous fibre, of which the meshes are more or less 

 oblong, passing into prominent longitudinal lines on the 

 branchlets, where they terminate on the backs of the semi- 

 tubular plates which respectively form the floors of the hydro- 

 thecse, to which they thus give support. Size of specimen, 

 which is merely a branch, 4^ inches long by 2 broad. 



Hab. Marine ; procumbent. 



Log. Port Natal. 



Obs. The spines on the surface distinguish this from the 

 foregoing species, add to which its longer and more pointed 

 branches, longitudinally ridged clathrate fibre, and rich red- 

 pm-ple colour. It bears the no. " 72. 8. 1. 17, from Port Natal." 



In Dr. Gray's two Australian species there are no actual 

 spines independently of the projecting portion of clathrate struc- 

 ture on the proximal sides of the hydrothecas, and the " spinu- 

 lose" little knobs on the surface of Ceratella fusca. 



The hydrotheca in Dehkella atrorubens is formed of a simple 

 scoop-like projection of the subrectangular clathrate structm'e 

 of the stem, stopped at the bottom by a septum of the same ; 

 there is no decided hole there larger than the diameter of the 

 common mesh, for the coenosarc of the interior to communicate 

 with the sarcode of the polype, as in the Cape species ; while 

 in Ceratella fusca, which is almost as delicate in its branches 

 as a Sertularia, and not unlike it in the alternate, but here 

 spiral not opposite, position of its hydrothecaj, the latter are 

 formed by a projection of the clathrate tissue in the shape of 

 a clam-shell, whose ribs, extended beyond the margin, end 

 respectively in an inflated tubercle of the same kind as that 

 which characterizes the surface of the stem, rising up like 

 little knobs on the knots of the clathrate network, to which 

 Dr. Gray (7. c.) has appropriately applied the term "spinulose;" 

 the bottom of the hydrotheca is filled up with a clathrate 

 septum, in which there is no decided hole present as in the fore- 

 going species ; and in this way both of these from Australia 

 differ from those of the Cape of Good Hope. 



