802 MR. J. RITCHIE OX HTDROiDS [May 24, 



Family Campanulinid^. 



* Opercularella lacerta Johnston, p. 812. 

 *Cahjcella oligista, sp. n., p. 813. 

 Cuspidella costafa, Hincks, p. 814. 



Family Lafoeid^. 



Lafoea serraia Clarke, p. 815. 



* „ ?;ejiMs«a Allmaii(?), p. 815. 



Family Sertui-arid.*;. 



* Seriularella CJ/lind/rica Bale, var. pusilla, n., p. 817. 



„ polyzonias L., var. cornuta Ritchie (?), p. 81 8. 



* ,, quadridens Bale, p. 818. 

 Idia jyristis Lamouroux, p. 820. 

 JDiphasia digitalis Busk, p. 821. 

 Sertularia turbinata Lamouroux, p. 821. 



Family Plumularid^. 



Flumularia setacea Linn. (?), p. 822. 



„ sp. indet., p. 822. 



Antenella sectmdaria Gmelin, p. 822. 

 Lytocarpus pennarius Linn., p. 822. 



„ phos7iiceus Busk, p. 823. 



• indicates a species recorded for the first time from the Indian Ocean. 



Systematic Discussion. 



I. GYMNOBLASTEA. 

 Family Clavid.e. 



CORTDENDRIUM SESSILE, sp. n. (Plate LXXVI. figs. 1 & 2.) 



Teophosome. — Colony small, the largest of the three collected 

 being only 37 mm. in height. The stem is strongly fascicled, 

 1'5 mm. thick towards the base, and straight. It may divide 

 into main branches, which are beset by numerous smaller, almost 

 equal branchlets, about 1 mm. in length. These spring from 

 two opposite sides, and lie roughly in one plane. The branchlets 

 on any one side are almost equidistant from each other, but their 

 positions bear no regular relation to those of the opposing series. 

 They taper very slightly towards the base, but there is no trace 

 of ringing nor of wi'inkling. 



The majority of the hydranths spring from tubes on the anterior 

 sui'face of the branclilets, although a few are also sca,ttered on the 

 main branches. The hydranth tubes do not become free from 

 the common fascicle, except rarely and for an extremely short 

 distance ; nor are special hydrophore-like portions developed. 

 Thus the hydranth projects simply from the open mouth of a 

 tube, the adcauline wall of which is adnate. The hydranth tubes 

 [4] 



