38 PEOF. p. MARTIN DUNCAN'S EEVISION OF THE 



Grenus Diblastjs, Lonsdale in Dixon's G-eol. Sussex, 1850, p. 248 ; 

 Duncan, Brit. Foss. Corals, Sitpp., Pal. Soc, Part ii. No. 1, 

 1869, p. 14. 



Colony incrusts and is very irregular in shape. The calicos 

 are wide apart and project ; the columella is formed by the 

 junction of the larger septa, and is parietal and rudimentary. 

 The septa are dentated, crowded and granular laterally. PaU 

 absent. The costse are granular, equal or subequal, and often 

 extend across the eoenenchyma to neighbouring calices. 



Gemmation marginal and intercalicinal. 



Distribution. — Fossil. Upper Cretaceous : England. 



II. Alliance LOPHOHELIOIDA. 

 Oculinidse with dendroid and bunch-shaped colonies. Corallites often 

 coalescing ; gemmation alternate. Septal arrangement irregular. Colu- 

 mella absent or rudimentary, tubercular, or spongy, or styliform. Tabulae 

 or dissepiments present or not. Mural structures thickening with age. 

 Septa enthe or subentire, often exsert. 



Genus Lophohelia, Ed. & H. 



Genus Amphihelia, Ed. & H. 



Genus Enallohelia, d'Orb. 



Genus Euhelia, Ed. & H. 



Genus Acrohelia Ed. & H. 



Genus Astrohelia, Ed. & H. 



Genus Dendrohelia, Etallon. 



Genus Lophohelia, Milne-Edwards Sf Jules JECaime, Compt. Mend, 

 de VAcad. des Sci. t. xxix. p. 69 (1849) ; P. Martin Duncan^ 

 Trans. Zool. Soc. Lond. vol. viii. pt. 5, p. 330 (1873). 



The colony is dendroid, and its gemmation is subterminal and 

 irregularly alternate ; the granulated wall is thick and increases 

 in thickness with age. The calices are very deep ; the septa are 

 well developed, exsert, entire, and unite more or less at the 

 bottom of the calicular fossa. Arrangement of septal orders 

 irregular. Columella absent or false ; costse near the calicular 

 margin. Dissepiments may exist, and often well-developed 

 tabulae, which close in the calice inferiorly. Internal cavity not 

 filling up much with age. 



Distribution. — Fossil. Miocene, Pliocene : Europe. — Secent. 

 Atlantic, N. & S. ; Caribbean Sea ; Mediterranean ; East Indies ; 

 Philippines. 



This genus has given much trouble in its classification, and 

 some time since I was disposed to place it in the Astrseidse ; but 

 its proper position appears to be here. 



