Eev. T. Hincks on British PoJyzoa. 213 



Suborder Cheilostomata, Busk. 



Genus Membranipora, De Blainville. 

 1. Membranipora nodulosa, n. sp. 



Zoooecia small, oval, margin slightly raised, granular, un- 

 armed ; more than half the area covered in by a minutely 

 granulated calcareous lamina ; orifice occupying rather more 

 than a third of the area, arched and somewhat contracted above, 

 lower margin straight, obscurely trifoliate ; at the base of each 

 cell a very large, prominent, smooth nodule, usually sub tri- 

 angular in shape : oooecia very small and shallow, rounded, 

 smooth. 



Colonies forming small and very inconspicuous crusts. 



Localities. Coast of Antrim [Hyndman) ; South Devon, off 

 Brixham (r. ^.). 



Distinguished from M. Rosselii^ to which it is allied, by the 

 much smaller size and oval form of the cell, the continuous 

 and very slightly granular margin, and the large and conspi- 

 cuous intercellular bosses or nodules. 



2. Membranipora aurita, n. sp. 



Zoooecia ovate, somewhat expanded below, disposed with 

 great regularity in quincunx ; area with a membranous cover- 

 ing, no calcareous lamina ; margin plain, on one side, about 

 halfway down, a blunt, short spine ; immediately above each 

 cell, or the ovicell, when present, two raised avicularia, one on 

 each side, with a pointed mandible, usually directed upwards 

 and slightly outwards : oooecia subglobose, partially immersed, 

 with a strong rib on the front, rising to a point above and 

 inclosing a triangular space. 



Colonies forming large, subcircular patches, resembling the 

 most regular lacevv^ork. 



Localities. Antrim {Hyndman) ; Cornwall and South Devon 

 (T. H.) ; Northumberland {Alder). 



Distinguished from M. Flemingii by the more regularly 

 ovate form of the cell, the entire absence of a calcareous 

 lamina, the triangular figure on the front of the ovicell, and 

 the perfectly regular quincuncial arrangement of the cells. 



3. Membranipora Jlustroides^ n. sp. 



Zoooecia large, in regular lines, set closely together, oval ; 

 margin Avith 12-14 massive, flattish, sometimes subclavate, 

 sometimes bifid spines, which bend inwards and meet across 



