LICHENOPORA RADIATA. 477 



openings (ooecial apertures) placed near the margin of 

 the central area. Zocecia much raised, connate, dis- 

 posed in uniserial radiating rows, alternately longer 

 and shorter ; orifice with the upper margin usually mu- 

 cronate, and sometimes the lower also ; one or two rows 

 of rather large subcircular pores between the lines of 

 cells. 

 Disk about §■ inch in diameter. 



This is a very pretty species, distinguished by the regu- 

 larity of its radiation and the alternation of long and 

 short rows of cells, which are uniserial and much elevated 

 above the surface of the zoarium. The innermost tubes 

 are the longest ; and there is a gradual diminution in 

 height towards the margin. The orifice is more or less 

 strongly mucronate, and is often bifid. 



The central area of the disk, which is of considerable 

 size, has the appearance of being irregularly reticulate, 

 and is covered with cancelli of very various shapes and 

 sizes. The pores between the lines of cells are much 

 larger, and more regularly formed; they are sometimes 

 uniserial and sometimes disposed in a double row. 



The zoarium, when attached to Algse, is often much 

 distorted, clasping and partly enveloping the stem, and 

 loses its characteristic neatness and regularity of appear- 

 ance. 



The ooecia are formed by a general inflation of the 

 upper surface of the disk, the trumpet-shaped processes 

 being the orifices. 



Habitat. On shells, sea-weed, &c., from moderate 

 depths and (?) deep water. 



Localities. South Devon, Brixham, Salcombe, &c. 

 (T. H.). 



Geographical Distribution. Mediterranean (^Porcu- 

 pine ' Exped.) : Adriatic (Heller) : Naples, common on 



