304 NATURAL HISTORY OP 



tured. The ovicels are arranged round the zoarium, 

 and are ovate witli a tubular orifice. 



FAMILY III. HORNERID^. 



Zooecia opening on one side only of a ramose zoarium ^ 

 Qiever^ adnate and repent. — T. H. 



Genus I. Hoenera, Lamouroux. 

 Named after Mons. Horner. 

 Zoarium erect, ramose, sometimes reticulate. Zooecia 

 tubular, opening on one side only of the branches, dis- 

 posed in longitudinal series, the celliferous surface 

 often traversed by wavy anastomosing ridges. Ooecium 

 a distinct chamber (not a mere irregular inflation of 

 the surface of the zoarium), placed dorsally or in front. 

 — T. H. 



1. H. LICHENOIDES, LiuncBus. 



Millepora lichenoides {Linn., Mull,, Esper, Fahr.), 

 Hornera frondiculata {Sars., Bush), H. borealis {Bush, 

 Alder) . 



Hab. : Shetland, Hebrides {A. M.N.). 



This is a northern form, in which the zoaria are erect 

 and rise to a height of about an inch. The branches 

 divide dichotomously, and form fan-shaped segments. 

 The front surface is reticulately marked, and is also 

 punctured. The zooecia open on the front and sides 

 of the branches with circular orifices ; those on the 

 front are almost entirely immersed, those on the sides 

 project slightly in a tubular manner. The back of the 

 zoarium is marked by waved lines. 



2. H. viOLACEA, Sars. 

 Pustulopora Orcadensis {Bush). 

 Hab. : Shetland {A.M.N., C. W.P.), 



