REPORT ON CORALS— DEEP-SEA MADREPORARIA. 131 



such closely similar forms, and actually place them in separate Orders with all the 

 Oeulinidas, Astrasidfe, and Eupsammidse between them. I have no doubt that the soft 

 structures in the two genera will, when examined, be found to be closely similar. If the 

 Eugosa are to be maintained as a separate Order, it must be retained to include only 

 Palaeozoic forms, which differ in more important particulars. It may be that recent 

 forms, such as Duncania, form a stepping-stone to the Eugose corals generally ; of their 

 close affinity with some of them there can be no doubt, when such eminent authorities as 

 Duncan and Pourtales agree upon the matter ; but either those corals at present placed 

 amongst the Eugosa with which they are allied must be separated from the old Order, 

 or the Order itself must be given up as such. There can be little doubt that a system 

 of classification which places a separation of ordinal importance between the genera 

 Theeocyathus and Duncania must be in the highest degree unnatural. I have had no 

 opportunity as yet of studying the structure of Palaeozoic corals myself, and therefore 

 wish to write with all due deference on the matter. Professor Martin Duncan, has 

 expressed somewhat similar views to me on the question. 



In examining specimens of Bhizotrochus typus in the British Museum, I was struck 

 by the close similarity in structure displayed by its exothecal roots to those of Duncania. 

 They are of the same texture on the surface, and are striated in a similar manner. Inside 

 the calicle several thin narrow plates of hard tissue are developed running all round the 

 calicle just within its mouth, and parallel to its wall. These seem to represent the 

 stereoplasma. Moreover, the septa are extremely irregular, and in neither young nor 

 older specimens is an arrangement of the septa in sixes well marked. In the oldest and 

 largest specimen sixteen septa are thicker than the rest, and are prominent near the 

 centre of the calicle and, so to speak, " primary." The frequent arrangement of the septa 

 in sixteens in Caryophyllia communis will be found noted under the description of that 

 species. The genus Neohelia described in the sequel is remarkable for having its septa 

 arranged with perfect regularity in fives, a condition which occurs also in some forms of 

 Madracis. 



With regard to the distribution of the deep-sea Madreporaria, it appears that, as 

 in the case of other deep-sea animals, they are mostly very widely distributed, indeed 

 some, as for example Bathyactis symmetrica, have a world-wide range. Examples 

 of the genus Flabellum appear to be rather scarce off the north-east American coast and 

 the West Indies, and no Flabellum was described in Pourtales' first list of deep-sea corals 

 from those localities ; but Flabellum angulare was dredged by the "Blake," and a new 

 species of Flabellum was obtained by Mr A. Agassiz on his late expedition. Moreover, 

 Mr Verrill has described another species Flabellum gooclii, as dredged in 220 fathoms on 

 the eastern slope of Georges Bank. At present the only genera which seem to be 

 restricted in range are Stephanophyllia and Sf)henotrochus, which have as yet been 

 obtained only from the seas of the Malay Archipelago in comparatively shallow water, 



