I'AMILIES A.ND GENEEA OP THE MADBEPORARIA. 37 



The very considerable changes in the definition of the family 

 Oculinidse prevent its being a large one in spite of the additions 

 made by palaeontologists and those naturalists who have described 

 the corals of the deep sea. 



There are, after revision, 21 genera. Eleven genera disappear 

 and one becomes a subgenus. A genus is relegated to the 

 AstrseidsB. 



The 21 genera are included in 5 Alliances— the Baryhelioida, 

 the Lophohelioida, the Oculinoida, the Prohelioida, and the 

 Stylophoroida. 



I. Alliance BARYHELIOIDA. 

 Oculinidae with massive or incrusting colonies. Columella absent and 

 pali also, or a false columella may be present. Septa variable in arrange- 

 ment. Coenenchyma well developed between the calices. 

 Genus Baryhelia, Ed. & H. 

 Genus Neohelia, H. N. Moseley. 

 Genus Diblasus, Lonsdale. 



Genus Baethelia, Milne-Edwards Sf Jules Haime, Hist. Nat. 

 des Gorall. vol. ii. p. 125 (1857). 



Colony massive. Calices slightly projecting or not, small. 

 Septa few, entire, thick and short. Columella and pali absent ; a 

 large open fossa existing in the axis of the corallites. Coenen- 

 chyma moderately developed, smooth or finely granulated. Dis- 

 sepiments rudimentary. 



Distribution. — Fossil. Cretaceous : Europe, England. 



Genus Neoheita, Moseley, Report on ' Challenger ' Corals, 

 p. 176, plate s. figs. 7, 7 a (1881). 



Colony with a very abundant and diffuse coenenchyma incrust- 

 ing the stems of Gorgonoids with very short branches only. 

 Calices with the septa arranged in five systems, which are often 

 fused together by the coenenchyma; a deep fossa exists, but 

 no columella. Gemmation irregularly dichotomous. 

 ^Distrihuiion. — Recent. Pacific : off Api Island, New Hebrides. 



It may be noticed that the surface of the eoenenchym.a which 

 separates the calices is marked by very slightly elevated rounded 

 ridges, which traverse it irregularly but with a general longi- 

 tudinal direction, and are continuous at the margins of the 

 calicles with the short costse. The primary and secondary septa 

 meet in the fossa. 



