BRITISH ZOOPHYTES. 257 



FAMILY XII. PORINID^, D'OrUgny. 



Zoariiim incrusting, or erect and ramified. Zooecia 

 with a raised tubular or suhtuhular orifice, and frequently 

 a special pore on the front wall. — T. H. 



Genus I. Poeina, D'Orhigny. 



Zooecia tubular or subtubular above, with a terminal 

 circular orifice ; a median pore on the front wall. 

 Zoarium (in the British species) incrusting, or erect 

 and ramose. — T. H. 



(a) Zoophyte erect, branching. 



1, P. BoREALis, Busk. 



Pustulipora gracilis (Sars), Onchopora borealis {Bush, 

 McA.), Quadricellaria gracilis {8ars., Aid.), Anarthro- 

 pora borealis {Smitt), Tessaradoma gracile (A. M. N.), 

 T. boreale (Smitt). 



Hab. : Shetland {A. M. N.). On stems of Tiihularice 

 and Sertularice, from deep water. 



Height 1—2 in. 



This species is white and dichotomously branched. 

 " The cells are ovate, arranged in four longitudinal 

 rows alternating regularly with each other, so that the 

 opposite cells are on the same level.^' Each cell has 

 a row of pores round its margin, and one or more small 

 circular avicularia. 



(b) Zoophyte incrusting. 



2. P. TUBULOSA, Norman. 



Lepralia tubulosa {A. M. N., T. H.), Anarthropora 

 monodox forma minuscula (Smitt), Cylindroporella 

 tubulosa (T. H.). 



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



s 



