LICHENOPORA llEGULARIS. 479 



The central part of the disk and the interspaces between 

 the rows of cells are cancellated or pierced by nume- 

 rons pores ; but this portion of the structure is very often 

 concealed by the ooecial inflation (formed of a thin cal- 

 careous crust) , which generally occupies the whole of the 

 upper surface and incloses the erect tubes, so as to di- 

 minish their apparent height. 



The ooecial orifices, according to Smitt, range from 

 1 to 8 ; very commonly there is only one. 



L. verrucaria is a northern, and specially an Arctic 

 form. 



Habitat. On Laminaria, stems of zoophytes, &c., from 

 moderate depths (15 fathoms) to deep water. 



Localities. Orkney (Barlee) : Arran (Busk) : Co. 

 Down (Hyndman). 



Geographical Distribution. Bahusia (Loven) : Nor- 

 way (Lilljeborg) : Finmark (Sars) : Davis Strait, 100 

 fathoms; Reykjavik, 15-20 fathoms ; Hamilton's Inlet, 

 Labrador (Wallich) : Assistance Bay, Greenland (Suther- 

 land) : Bay of Fundy (Packard) : St. George's Banks, 

 150 fathoms (Smith and Harger) : Nova Zembla, lat. 70° 

 30', long. 52° 45', in 5-20 fathoms ; Matotschkin-scharr, 

 2-5 fathoms, &c. ; Kara sea (Stuxberg and Theel) . 



b. Zooecia multiserial. 

 LicHENOPORA REGULARis, D'Orbiguy. 



Plate LXVIII. fig. 11. 



AcTiNOPORA REGULARIS, B'Orh. Pal. Fraii^'. torr. cret. v. 763, pi. dcclxiii. 

 figs. 7-9. 



Znarium entirely adnate, suborbicular, or somewhat ellip- 

 tical, flat above, with a slight depression in the centre, 

 a rather broad cellular margin sloping up to the rays. 



