Ivi BRITISH FOSSIL CORALS. 



4.. Genus Microsolena. 

 Lamouroux, Exp. meth., p. 65, 1821. 



Corallum differing from the preceding genus by the structure of the septa, the perfo- 

 rations of which are much larger than in Coscinarsea, and by the existence of a strong, 

 common epitheca. 



Typ. sp., Microsolena porosa, Lamouroux, op. cit., tab. lxxiv, fig. 24. 



5. Genus Goniopora. 



Quoy and Gaimard, Voy. de l'Astr., Zooph., p. 218, 1833 ; Goniopora and Porastrea, Milne Edw. and 

 J. Haime, Comptes rend, de l'Acad. des Sc., t. xxvii, p. 496, 1848. 



Corallum having distinct, elevated walls, of a fenestrate structure. Calices deep. 

 Columella spongy. Septa well developed, and fenestrate. No pali. 



Typ. sp., Goniopora pedunculata, Quoy and Gaimard, Voyage de 1'Astrolabe, Zooph., tab. xvi, 

 figs. 0-11. 



6. Genus Rhodar^ea. 



Milne Edw. and J. Haime, Comptes rend., t. xxix, p. 259, 1849. 



Corallum with thick walls, rather high. Septa rudimentary. Pali greatly developed, 

 and forming a rosette in the centre of the calice. 



Typ. sp., Rhodarcea calicidaris, nob. ; Astrea calicularis, Lamarck, Hist, des An. sans Vert., t. ii, 

 p. 266. 



7. Genus Porar/ea. 



Milne Edw. and J. Haime, Comptes rend., t. xxix, p. 259, 1849. 



Walls thin, and widely fenestrated. Septa formed by a series of spiniform processes, 

 which sometimes ramify towards the centre of the visceral cavity, so as to constitute a sort 

 of spurious columella. 



Typ. sp., Porarcea fenestrata, nob. ; Pocillopora fenestrata, Lamarck, Hist, des An. sans Vert., t. ii, 

 p. 275 ; Milne Edw. and J. Haime, Ann. des Sc. Nat., 3 rae serie, vol. ix, fig. 1. 



8. Genus IIolar.ea. 



Milne Edw. and J. Haime, Comptes rend., t. xxix, p. 259, 1849. 



Calices with distinct polygonal margins, rather deep. Septal apparatus composed of 

 irregular trabiculse, completely blended with the walls, and constituting thus a delicate 

 spongy mass. Columella fasciculate and short. 



Typ. sp., Holaraa Parisiensis, nob. ; Alveolites Parisiensis, Michelin, Icon. Zooph., pi. xlv, fig. 10. 



