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Show 440 PROF. P. M. DUNCAN ON DEEP-SEA [May 16, Cylicia tenella, Dana, which is placed amongst the Astrangiacese ; but the following structural peculiarities render this a matter of doubt. 1. Some corallites attain the height of fe inch nearly equalling 10 millimetres. 2. All the corallites do not arise from the stoloniferous base, but some spring from others between the calice and the base ; but it does not appear that these are buds. They are probably the result of polypes that became fixed on* to the epitheca of the original one in their mobile stage. 3. The epitheca is shown perfectly in small corallites; but the larger and even some of the smaller have distinct but small costse, which are marked with granules, and which join the angular and very slightly exsert ends of the septa. 4. The septal arrangement is irregular. There are six primary septa, and a number of others, the majority resembling the primaries. Usually there are 20 large septa reaching into the calice ; and between each pair there is often, but not invariably, a rudimentary septum. In some calices the primaries appear to be five in number; and in a bud there is one primary and a small septum on either side of it. All are granular and incised more or less. 5. The endotheca is absent, except within the calice of two specimens, where it is extending between the septa near the wall, as if commencing to occlude the floor of the calice. 6. The columella is formed of processes from the septal ends, is small, and has three or more beautiful granular ornaments on the points where the reticulations meet. The incised nature of the larger septa along their slanting internal margin is evident. Sometimes the septa do not even reach to the calicular margin ; and some appear as spines from the inner part of the calicular wall. The third cycle is rarely complete if the rudimentary septa, which project between the larger fe inch or a little more, are wanting, as in the diagnosis of Milne-Edwards and Jules Haime, ' Hist. Nat. des Corall.' vol. ii. p. 608 ; and the third cycle do not always bend towards the secondary septa. If the rudimentary septa are counted, the fourth cycle is rarely complete. The species Cylicia tenella and C. verreauxi, Ed. & H., differ in respect of the perfection of the third and imperfection of the fourth cycle, this last never being perfect iu either. There is no specific distinction between them; and therefore the last-named species had better disappear. The form under consideration I deem a variety of Cylicia tenella, var. natalensis (Plate X L . fig. 3). MADREPORARIA PERFORATA. Family EUPSAMMIN^E. BALANOPHYLLIA HELENA, sp. n. (Plate XLI. figs. 5, 6.) The corallite has a small base, a narrow bent cylindrical stem, and a suddenly large calicular opening. The costse are not exsert at the calice, are distinct to the base, |