480 LICHENOPORID/E. 



Zocecia multiserial, not raised above the surface, disposed 

 in regular radiating rows, which taper off towards the 

 centre, consisting of about three cells in the widest 

 part, orifice plain ; short rays intercalated at intervals 

 amongst the rest. 

 The longer diameter inch, the shorter rather less. 



THERE seems to be no essential difference between the 

 Shetland form, on which this description is founded, and 

 the Cretaceous species described by D'Orbigny as Actino- 

 pora regularis. The latter, as figured in the ' Paldonto- 

 logie/ is of rather smaller size than the recent specimen, 

 and seems to be in an earlier stage of development ; it has 

 a larger number of the short rays, bu* in all important 

 characters it agrees with the present. 



The zoarium is raised and somewhat mound-like, the 

 upper surface flat, very slightly depressed in the centre ; 

 and from this point the longer lines of cells radiate with 

 much regularity towards the circumference, widening 

 gradually as they approach it. There is no extension of the 

 lamina round the disk ; but a thick and compact cellular 

 border slopes up from the base of the zoarium to the circle 

 of celliferous rays. The latter number about twenty- 

 four in the Shetland specimen. The cells are not free for 

 any portion of their length ; but the orifices open out 

 uniformly on the surface of the rays. The shorter series 

 are few in number. 



This is a fine addition to our British fauna one of the 

 many which we owe to the energetic labours of our Shet- 

 land dredgers, and doubly interesting as the survivor of 

 so many important changes in the condition of our globe. 



HABITAT. On stone, probably from deep water. 



LOCALITY. Shetland (A. M. N.). 



RANGE IN TIME. French Cretaceous deposits at Sainte- 

 Croix, Vaud (D'Orbigny). 



