27(5 



ME. A. W. WATERS ON SOME 



examination by Mr, Busk " ; who would have placed it, she 

 considered, under Hornera if he had noticed the ovicell. 



In Idmonea I believe the ovicell is only known in I. radians^ 

 Lam., I. atlantica^ Forbes, I. ^t^acilUma, Busk, I. concava*, Eeuss, 

 I. serpens, L., I. ehoracensis, Busk, I. radicata, Kirkpatrick ; and 

 in all is on the anterior surface ; but both in Idmonea and Hor- 

 nera the position may be axillary, or far away from the bifurca- 

 tion ; and the position in relation to the axils can seldom or never 

 be looked upon as characteristic. I have before me a MS. list of 

 130 Idmonece, some of them synonyms, though all have been con- 

 sidered as separate species ; but only in the few cases mentioned 

 is the ovicell described. An ovicell has been figured by Hagenow 

 as Codlopliyma granulata on ^'Idmonea''' liclienoides, Goldf. ; but 

 I am not sure that this is a true Idmonea. 



Trom a list of 74 species of Hornera, it seems tliat the ovicell 

 is only known in H. frondiculata, Lam., H. foliacea, MacO., 

 H. violacea, Sars (practically dorsal), H. galeata, Sm., H. rohusta, 

 MacCx., S. ramosa, MacCx., S. lichenoides, L.t Goldstein (Trans. 

 Eoy. Soc. Vict. 1881, pi. ii. figs. 6, 7, 8) has named a ' Chal- 

 lenger ' specimen from Marion Tsland M. suh diih la, with. ovi- 

 cells but from the figure it might be HydrocoralUna. Keuss 

 has described as CoelopJiyma striata an ovicell which, as pointed 

 out by Manzoni, probably belongs to H. liippolyta, Defr. In 

 all these cases the ovicell is dorsal, forming a distinct chamber ; 

 and this is also the case in Hornera fissurata. In this last it 

 is longitudinally ridged, and in the furrows are pits, giving, 

 when not calcined, an areolated appearance. 



The position and nature of the opening of the ovicell is most 

 important, often, in fact, more so thau the shape of the ovi- 

 cell. The opening is, however, formed after the ovicell is com- 



* Not described ; but a recent specimen from Naples has the ovicell as a 

 raised chamber at the bifurcation. It nearly encloses one of the series, and 

 the ovicellular opening is by the side of the series. In another specimen 

 there is a slight central inflation bet\;veen the series ; but this does not seem to 

 be mature. 



t I find that H. lichenoides, L., occurs in Naples, together with H. frondi- 

 culata, and has an ovicell with a rib down the middle, as figured by Smitt 

 and Alder, whereas Hincks figures a transverse rib. It has been looked upon 

 as an exclusively northern form ; but the ' Challenger ' found it ofi" Monte 

 Video ; and, as mentioned, it lives in the Mediterranean. Among the ' Chal- 

 lenger ' material in Edinburgh I have since seen the ovicells on specimens from 

 Simon's Bay. These have a central rib, and also a transverse one from the 

 ovicellular opening to the median rib. 



