ALCYONAKIA. 305 



Plexaura praelonga, RIDLEY, var. elongata, n. 



Several incomplete specimens, dull crimson in colour, with two or three elongated 

 cylindrical branches, 3 millims. to 4 millims. in diameter and up to 30 centims. in 

 length. The axis, blackish-brown, 1 millim. to 2 millims. in diameter, is entirely 

 horny. The surface of the colony is covered with the pore-like apertures of the 

 polyps; around each aperture the spicules are disposed in a ring - 3 millim. to 

 0'5 millim. in diameter. 



The most characteristic spicules are very variable discs, " Blattkeulen," 0'4 millim. 

 to O'o millim. in length, with a rounded foliaceous expansion (0'3 millim. in breadth) 

 at one end and an irregular ramification at the other. The surface of the disc bears 

 a few large blunt tubercles. When the thin foliaceous expansions are broken off, 

 the rest of the spicule may be described as irregularly stellate. Actually stellate 

 forms also occur, and 3- to 6-rayed forms are represented. A few tuberculate spindles 

 occur here and there. 



As regards types of spicules, this form resembles Plexaura pralonga, but the 

 details of the " Blattkeulen," the rough cortex and the crimson colour, and some 

 other features, mark it as quite distinct from RIDLEY'S varieties typica and cinerea. 



Plexaura antipathes, KLUNZINGER, var. flexuosa, n. 



To a variety of this species we refer two specimens, the larger of which measures 

 120 millims. in height and the same in width. The colonies are bush-shaped and 

 very profusely branched, with the branching not confined to one plane. The branches 

 are sometimes thickened during a part of their length, while all are swollen at the tip 

 into a knob or club-shaped portion, which measures from 2 millims. to 3 millims. in 

 diameter. 



The polyps are scattered over the whole surface of the stem and branches. No 

 projecting calyces are present, but the position of the polyp is marked by an oval or 

 circular opening, round which the coanenchyma is slightly raised. 



The axis is thick at the base, measuring 3 '5 millims. in diameter, but it becomes 

 slender and thread-like at the tips of the branches. The colour is a dark brown, very 

 little difference being seen throughout the whole ramifications of stem and branches. 

 The base consists of a broad, flat, spreading portion, from which in one specimen 

 several stems rise in addition to the main stem. 



The spicules are short, many branched, rod-like needles or small spherical bodies, 

 which bear many protuberances. They measure, length by breadth in millimetres, as 

 follows : 012 X 0-08 ; 0'12 X O'lO ; 0'14 X 0'08 ; 0'15 X O'lO ; 0'20 X OD8. 



The colour of the colony is a dirty greyish-white, with a light brownish tinge in 

 many places. 



Though differing slightly from Plexaura antipathes, yet the differences are not 

 sufficient to warrant the formation of a new species. See HILES (1899), pp. 51-2; 

 WHITELEGGE (1897), pp. 317-8. 



Locality : Gulf of Manaar. 



2 R 



