. Report on the scientific results of the voyage of Challenger during the years 1873-76 : under the command of Captain George S. Nares, , and Captain Frank Turle Thomson, . ies where these are not present, lying next to the primaries, higher thanthe tertiaries, or equal to them. Columella absent or little prominent. I have formed this genus to contain four species of corals dredged by the Challengerwhich are evidently very closely allied, but for which it is nevertheless somewhat difficultto find generic characteristics in the terms of the ordinary designation of genera.
. Report on the scientific results of the voyage of Challenger during the years 1873-76 : under the command of Captain George S. Nares, , and Captain Frank Turle Thomson, . ies where these are not present, lying next to the primaries, higher thanthe tertiaries, or equal to them. Columella absent or little prominent. I have formed this genus to contain four species of corals dredged by the Challengerwhich are evidently very closely allied, but for which it is nevertheless somewhat difficultto find generic characteristics in the terms of the ordinary designation of genera. I placedthe four species provisionally in my Eeport on Corals in the genus Ceratotrochus. 152 THE VOYAGE OF CHALLENGER. Stephanotrockus diadema, Moseley (PL III. fig. 1, a-c). Geratutrochus diadema, Moseley, Proc. Roy. Soc, 1876, p. 553. The coralluni is white and saucer-shaped. The central region of the base is flattenedand nearly horizontal, the lateral portion of the wall rises with some abruptness from thishorizontal region at an angle of about 55° with the vertical. A very short rudimentarypedicle is seen in the centre of the base and terminates in a small scar of Stephanotrockus diadema. (Once and a half the natural size.) From the base of the pedicle radiate out well-marked costal ridges corresponding to theprimary and secondary septa. These ridges are sharp and serrate, the dentations beinginclined towards the margin of the calix. The primary costa are more prominent thanthe secondary, and take origin nearer the peduncle. Tertiary costse are present as onlyslightly elevated narrow untoothed ridges, most marked near the margin of the calyx; thequaternary costa are very faintly marked. There are six systems of septa and five whole of the septa are exsert, the primary and secondary extremely so, projectingnearly a centimeter above the margin of the calicle ; the quinary septa next to the primaryand secondary are higher than the quaternary an
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectscienti, bookyear1881
