16 
10. Stylaster tthatus sp. n. Plate Il, fig. 15. 
Stat. 105. 6°8’N., 121° 19 E. Sulu Ils. 275 M. 1 Ex. and fragments. 
A fine specimen of this species was obtained, one of the few that showed the base of 
attachment. The branches are flabellate, but are arranged more or less in tiers, so that they 
often overlap each other. The main stem (before it spreads out at the base) is 12 mm. in 
diameter, but this immediately divides into six stout branches which measure about 3,5 mm. 
at the base. Two main branches are anastomosed, but this seems to be an exception; the finer 
branches show no anastomoses. The colony is 50 mm. high and about 90 mm. broad. In 
spirit specimens the surface of the coral appears smooth, but when calcined, there appear 
delicate, irregular longitudinal ridges and very fine scattered pores, with a few larger ones 
between them. The minute pores are the same as the dotted striations found in other species 
of Stylaster, that is to say coenenchym pores. The larger pores probably contained batteries of 
nematocysts similar to those described by Moserry in Aséty/vs at the outer edge of the septa 
and in Cryptohelia both there and on the lid. The colour is yellowish white. The cyclosystems 
closely resemble those of Stenohelia, their openings all face one way and the gastropore is 
very deep and curved, with the style at the bottom, lying parallel to the axis of the branch, 
but there is a distinct, well developed style in the dactylopore, while in S¢exohelza it is absent 
or very rudimentary. The Cyclosystems are more or less round in shape with a diameter of 
about 1,2 mm. and about 2 mm. apart; they are only slightly raised above the surface of 
the coral. Owing to the great growth of the coenenchym of the older branches, the cyclosystems 
lie on the upper surface, instead of jutting out on each side alternately. There is no external 
evidence of gonads. In one or two instances cyclosystems have been converted by a parasitic 
Cirrhipede into large globular masses 2 mm. in diameter. 
This species may be defined: 
Hydrophytum sub-flabellate, substantial; surface of corallum smooth; cyclosystems all 
directed towards one surface, gastropore very deep and curved down the stem. 
11. Stylaster umbonatus sp. n. Plate Il, fies; 16" and 17. 
Stat. 119. 1°33 .5 N., 124° 41°E. IN. of (Celebes: oor (Mi Iwo) “pieces) fone) terminally the 
other basal. 
This deep sea species forms a delicate flabeilum, with occasionally anastomosing branches. 
Its most marked peculiarity is that the surface is covered with large blunt spines (Fig. 17), 
which are oval in section, their long diameter (from 0,2 to 0,4 mm.) lying lengthwise to the 
branch. On the younger branches these spines occur on the sides only; they are also longer in 
proportion to their breadth. Longitudinal ridges also appear on the younger branches only. The 
height and breadth of the colony are both about 30 mm.; the base of the main stem is 2 mm. 
in diameter, the stem at the base of the terminal branches 0,6 mm. The colour is yellowish 
white. As in S. “datus, the cyclosystems all face towards one surface of the flabellum, the 
gastropore is deep and curves down the stem and there is a distinct style in the dactylopore as 
well as at the bottom of the gastropore. The cyclosystems are oval in shape, often more or 
