EEPOET OX THE ALCYOXARIA. 113 



one plane, of 200 mm. in height ; the main axis has a thickness at its base of 2 mm., 

 but the diameter of the tenninal branches is nearly 4 mm. A principal stem can 

 be distinguished, from which branches are given ofi" on both sides ; some of these attain 

 the thickness of the principal stem ; they are given off both at right and obtuse 

 angles, soon bending upwards, and then running parallel to the chief stem. The 

 branches sometimes bear lateral twigs, which in their turn give rise to smaller offsets, 

 these are short and stand perpendicularly. In single branches a uniting or anastomosing 

 takes place by obliquely uniting branches. The ccenenchjTiia which covers the horny, 

 flexible axis, is thick, and towards the apices of the branches it becomes more so, so that 

 the terminations of these appear quite club-shaped. The polyps, both on the stem and 

 branches, are crowded all round the periphery, the pol}'ps being at right angles to the 

 stem ; they are cylindrical, with upright truncated calyces. The opercular region does 

 not project. The polyps measure 8 to 1 mm. in diameter. The spicules of the 

 ccenenchjTna are either spindles, with tubercles which are often branched, occasionally 

 thickened at one end, or at both ends, and often also feebly curved, or some form lateral 

 prominences, which are branched, wdth spiny tubercles. The spicules of the pol}'p 

 calyx are very characteristic. These are pointed spindles, with expanded basal portions, 

 which give rise to from two to six downwardly directed lobes, provided with simple or 

 complex spines ; the basal portions of these lie tightly packed over one another, like 

 tubes, while the apices project and are often very conspicuous around the margins of 

 the polyps. The opercular coverings are composed of thin, fusiform spicules, placed on 

 the basal portion of each tentacle ; three or four will be found converging towards the 

 apex of each tentacle. While the spiciiles figured by Eidley fairly well represent those 

 found in the Challenger specimen, yet it may be noticed that many have been observ'ed 

 by us with much more delicate and ornamented branches of the singular basal portions 

 than are figured on pi. xxxviii. of Ridley's paper. The colour of our specimen is a 

 dark red. 



Habitat. — Station 203, off Panay, Philippines ; depth, 20 fathoms ; bottom, mud. 



Genus 8. Placogorgia, n. gen. 



Stem upright, branched in one plane, with a horn)-, flexible axis and a thick 

 coenenchyma, on which the polyps are arranged in narrow spu';ils. The poh-j>s are 

 short, cylindrical, and flattened on the oral aspect. The upper portions of the polyps, 

 with the greater portion of the tentacles, can be quite withdrawn, being then covered 

 over by the basal portions of the tentacles, which with their spicules form an operculum. 

 The spicules of the coenenchyma are warty spindles, often bent on their long axis. The 

 pol}^ spicules are broad, warty " Stachelplatten," which lie over one another like scales ; 

 often these are replaced by iiTcgular discs, whose surface is covered with papilhv> and 



(ZOOL. CHALL. EXP. — PART LXIV. — 1887.) Sss 15 



