REPORT ON CORALS— DEEP-SEA MADREPORARIA. 207 



are derived from the main branches next the primary septa, whilst only two are derived 

 from those next the secondaries. A distinct deltoid arrangement is observable in the 

 disposition of costal trabeeulse. The outer trabecular next the primary septa are straight 

 or nearly so for their entire length, running parallel to and close beside the primary 

 septa ; all their branchings appear to occur on their sides lying next the secondaries. 

 Thus each system is complete in itself, and more or less separate both above and below 

 in the corallum ; the crossings of the costal trabecula under the septa, necessitated by 

 their different mode of branching, are confined to the interior of each system. So regular 

 are the bifurcations of the septa that I am at a loss to designate the quinary, quaternary, 

 and tertiary septa in each system as such, the terms would seem hardly to apply. The 

 costal trabecular appear to grow first in the development of the coral, as is shown by the 

 projection of them at the margin, without corresponding septa developed as yet above them. 



The animal of the present species is flat and discoid, and of very small elevation 

 except around the mouth, which is elevated at its margin above the disc (PL XVI. 

 fig. 4). The tentacles are elongate, conical in form, with large rounded knobs at their 

 tips. There are six small but long tentacles placed upon the disc at about one-third of 

 the distance from the margin to the centre, and over the primary septa. At the margin 

 of the disc there are tentacles of two sizes, larger and smaller, which alternate with one 

 another, the smaller being placed at a slightly higher level on the edge of the coral than 

 the larger, which lie in the same place as the disc itself. There are twelve marginal 

 tentacles, six large and six small, in each system. The tentacles correspond in position 

 to the intervals between the marginal spines that is to the lines of the septa. The 

 larger tentacles correspond to the intervals between the marginal spines which are least 

 deeply indented. The tentacles are probably absolutely non-retractile. The entire disc 

 of the animal to its very margin, which coincides with the tips of the marginal spines, 

 was coloured, in a fresh specimen examined, dark madder ; the mouth was of a light 

 orange colour ; the tentacles transparent and colourless, with opaque white tips. The 

 thread cells in the knobs of the tentacles were found to be of a similar form to those 

 occurring in the tentacles of Corallimorphus profundus (Moscley) of the very elongate 

 cylindrical form. 1 



Extreme diameter of the fresh animal between the tips of the tentacles, 38 mm. 

 Extreme diameter of the corallum, 25 mm. Extreme height from the centre of the base 

 to the tips of the spines of the septa, 2 mm. 



Four specimens in all of this coral were obtained on three occasions in deep water 

 in the Southern Atlantic and South Indian Oceans. 



Station 147, in the Southern Indian Ocean, 80 miles west of Hog Island, Crozette 

 Islands. Lat. 46° 16' S., long. 48° 27' E. 1600 fathoms. 



1 H. N. Moseley, On New Forms of Actiniaria Dredged in the Deep Sea, Trans. Linn. Soc, 2 ser., Zoology, vol. i. 

 p. 300. 



