330 PROFESSOR P. M. DU^'C4JS^ ON THE 



The septa are not incised on their free margins, and are remarkable, so far as their 

 number is concerned, for their very irregular cyclical arrangement. Some primary 

 septa are very large, exsert, and project outwards; Others of the same cycle are not 

 much larger than the secondaries, and barely project at all. 



The costae may be but faint striations, or distinct crests on corallites of the same 

 stem ; and occasionally not a trace of any other markings than the granulation of the 

 wall may be observed. 



The position of the gemmation varies greatly, and may be on the calicular margin, a 

 little way down or some distance down the wall on the same corallum ; and the rest 

 of the corallite varies as much as the other details. 



I cannot understand why Lo^hohelia should be classified with the Oculinidae, whose 

 essential peculiarities are given by MM. Milne-Edwards and Jules Haime, Hist. Nat. 

 des Corall. vol. ii. p. 102. 



In estimating the value of their differentiation, it must be remembered that lateral 

 gemmation is common to other families, that thick imperforate walls are so also, and 

 that the thickness of the wall in the Oculinidse is not produced by what is termed 

 ccenenchyma in the aggregate Astrseidse. 



The paucity of the peculiar endotheca is not characteristic. But the fiUing-up of 

 the visceral cavity is rather peculiar, and in a general sense may be sufiiciently corre- 

 lated with the other characteristics to form a structure common to the family. 



A careful examination has not proved that this filling up occurs in Lophohelia. 



Loplwhelia, as a genus, possesses entire septa ; and as it has endotheca, and no true 

 ccenenchyma, it must be associated with the Eusmiliinse, amongst the Astreeidse. 



The groups of the Trochosmiliacese and Euphylliacese will not admit the genus ; but 

 it is evidently closely allied to the genus Dendrosmilia of the Stylinaceae (indcpendantes, 

 Ed. & H.), oj>. cit. p. 220. 



I therefore propose to remove the geuus Lophohelia from the Oculinidae, and to 

 re-write its generic diagnosis. 



Family AstrSBidsB. 



Subfamily EusmiliiNjB. 



Division Stylinace^. 



Section Sttlinace^ independentes. 



Genus Lophohelu. 



The corallum is dendroid, and its gemmation is subterminal and irregularly alternate. 



The wan is very thick. The calicos are very deep. The septa are irregular in their 



cyclical arrangement. There is no columella. There are dissepiments, and strong 



well-developed tabulae. 



