EADIOPOEA. 
283 
Type Species. 
Madiopora formom (Michelin), d’Orbigny, 1849. CeDomanian : 
France. 
Affinities. 
This genus is the culminating ’form of a long series beginning 
with the simple discoid Disoocavea, and including Tholopora, which 
is composed of cylindrical stems made up of superimposed sub- 
colonies, and the arborescent Radiocavaria. 
One species that may belong to Radiopora has the radial 
arrangement of the apertures imperfectly developed ; hut as a rule 
the surface of the zoarium is marked by conspicuous stellate groups 
of round apertures. 
1. Radiopora formosa (Michelin), 1846. 
Synonymy. 
Ceriopora formosa, Michelin, 1846. Icon. Zooph. p. 206, pi. lii. fig. 6. 
Radiopora ,, pars, d’Orbigny, 1850. Prod. Pal. vol. ii. p. 176. 
,, ,, d’Orbigny, 1854. Bry. Cret. p. 996, pi. 782, figs. 1, 2. 
Stellipora ,, von Hagenow, 1851. Bry. maastr. Kr. p. 44. 
Diagnosis. 
Zoarium large, with an expanded incrusting base, and a short 
constricted stem which expands above into a large mass, 
bearing numerous thick, knobbed, or pointed branches. 
Apertures in conspicuous radial groups. 
with about four 
apertures in each radial row. 
Dimensions. 
Micbelin’s type. 
mm. 
Height of zoarium 
Diameter of zoarium ... 
... over 28 
36 
Diameter of base 
21 
Diameter of stem above base ... 
15 
Diameter of radial group 
3-5 
Disteibution. 
British : 
Upper Greensand : Maiden Bradley (two specimens) . 
Foreign : 
Cenomanian : Le Mans. 
Affinities. 
This species is the type of the genus. It is not, however, very 
well known; it must be rare in France, as d’Orbigny copied 
