490 Happon— The Actiniaria of Torres Straits. 
Owing to the great development and prolongation of the cesophageal grooves, the 
directives are feebly developed even in the lower part of the ccelenteron, and so 
far as I could discover they were sterile. The endoccels of the twenty-four 
mesenteries are prolonged into the lobes of the oral disk, and these show a variable 
degree of prominence corresponding with the mesenteric cycle to which each 
belongs. The twenty-four lobes which correspond to the exoccels are distinctly 
smaller than the others, and are situated more towards the periphery of the oral 
disk. The cesophagus is large and deep, and provided with two large, very deep, 
and elongated gonidial grooves. 
Actinodendron plumosunm, nN. sp. 
Actinodendron arboreum (Q. & G.) Hadd. & Shackl., 1893; Proc. R. D.S8. vimt., 
p- 117, not of Quoy et Gaim. 
aleyonoideum, Saville-Kent, 1893, ‘‘ Great Barrier Reef,” 
pp. 34, 146, pl. xxi. a., not of Quoy et 
Gaim. 
a alcyonidium, : Saville-Kent, 1897, Naturalist in Australia, 
p. 2238, fig., p. 224. 
(PIS Xe.) figsas—6.) 
Form.—Column soft; no warts or suckers; transversely corrugated when 
contracted, smooth when extended. The oral disk is prolonged into forty-eight 
tentacle-like lobes, of which the outermost cycle of twenty-four are distinctly the 
smallest in size, though usually in a distended condition the lobes are, however, 
contractile, and are covered with branched tentacles, which appear to be spirally 
disposed; the fully developed tentacles have quite a tree-like appearance; the tips 
of the bluntly pointed branches have on their oral aspect two slightly diverging 
thickened oval patches ; the column passes into the lobes without any specialised 
capitulum or parapet. Mouth oval, may be raised to a cone, with two gonidial 
grooves. 
Colour (Specimen A).—Column uniform yellow ; tentacles and oral disk cinder 
colour ; the twenty-four radial areas corresponding to the exoccels yellowish, with 
dark-grey spots. 
(Specimen B).—Column yellowish, but rather pinkish below, with irregular 
brown streaks, which reach from the lower border to about one-third to one-half of 
the height of the column; tentacles cinder colour, with a pale whitish green tinge ; 
the characteristic colouration of the twenty-four radii occurs only on the outer half 
