THEONOID.E. 127 



1. H. RADIATA (n. up.) PI. XIX, fig. 2. 



Disciformis, subndnata. Superficie inferior! Integra rugisque concentricis ornata. 

 Cellularum orificiis, subovalibus, simplicibus superficie aequatis ; ostiolis interstitialibus 

 parvis, orbicularibus, foveolatis. 



Polyzoariuni discoid, adnate by a broad base, the unattached part of the under 

 surface covered with a thick, entire, calcareous layer, marked with annular ridges ; mouths 

 of cell-tubes suboval, simple, even with the surface ; intermediate orifices small, circular, 

 placed at the bottom of funnel-shaped depressions. 



Habitat. C. Crag, Sutton, S. Wood. 



Were it not for the existence of the interstitial tubes, which are of a moniliform cha- 

 racter, as in Heteropora pustulosa, this form would be hardly distinguishable from a 

 Defrancia or Discopora, with which it is undoubtedly closely allied. 



2. H. PARASITICA (n. sp.) PI. XXII, fig. 5. 



Incrustans, indefinita (?) Cellularum orificiis orbicularibus, simplicibus, superficie 

 sequatis ; ostiolis, orbicularibus, simplicibus, sparsis. 



Incrusting, indefinite (?). Orifices of cells circular, simple, even with the surface ; inter- 

 mediate openings circular, simple, irregularly scattered among the others. 



Habitat. Cor. Crag, on shell, S. Wood. 



This is a very doubtful form, but as I am unable to refer it to any known species, it 

 may be, provisionally at any rate, regarded as independent. In the figure the orifices of 

 the cells appear as if surrounded with an annular thickening, but this is not apparent in 

 the specimen, at any rate so distinctly as it is represented by the artist. The entire surface 

 between the openings appears irregularly areolatecl, and as if formed by the closed orifices 

 of cells, sealed up, as it were, by calcareous matter, as may frequently be observed 

 in other cyclostomatous Polyzoa. 



Fam. VI. THEONOIDjE, Busk. 



Polyzoario massivo, subgloboso vel irregulari ; cellulis contiguis, confertis. 

 Polyzoariuni massive, subglobose, or irregular ; cells contiguous, crowded 



