Z8 SYDNEY J. HICKSON ann F. H. GRAVELY. 
Up to a height of about 150 mm. the colony consists of only four or five thick 
(7 mm. in diameter) and occasionally anastomosing stems, bearing a few thinner 
(3 mm. in diameter) branches which are themselves pinnately branched. Above this 
recion the thick stems branch much more profusely and somewhat pinnately, bearing 
numerous thinner branches whose method of further ramification is always pinnate. 
The ultimate branches (hydrocladia) are jointed, the internodes being 0°6-1*1 mm. 
in length and about 0°4 mm. in diameter. Each internode hears on one side a single 
hydrotheca (hydrophore) adnate throughout its whole length, and supporting the 
base of a hydranth 2 mm. in length (fig. 24, /yd.), and on the opposite side a long 
serpentine dactylozooid (sarcostyle) 1°5 mm. in length and about 0°15 mm. in 
diameter (fig. 24, d.), supported at the base by a nematophore (sarcotheca) 0°15 mm. 
in length and about 0°15 mm. in diameter. 
At the extremity of the dactylozooid there is a battery of nematocysts. In the 
specimens many of the dactylozooids and nematophores are broken off, but there is 
little doubt that they are usually, if not regularly, present in the living colony in the 
position assigned to them. The dactylozooids are very similar to those figured by 
Hincks for Ophiodes mirabilis, although not so clearly “ knobbed” at the extremity. 
The hydranths are of the typical //alecium form. The hypostome is surrounded 
by a circle of about twenty tentacles each about 0°5 mm. in length. 
Gonosome.—The gonothecee together with some nematophores occur in 
“ coppinia” masses (fig. 28) on the stem and branches. These ‘“coppinia” masses 
are oval or spherical, densely branched and tangled clumps, 25 x 25 mm. to 
60 x 30 mm. in size, having a rough resemblance to the “ bedeguar” galls on the 
stem of the wild rose. The delicate dichotomously ramified branches of these 
masses bear dactylozooids and nematophores (fig. 29, d. and nph.) similar to those of 
the other parts of the colony, and numerous paired gonothece (fig. 29, gth.), 
1:0 x 0°7 mm. in size, which curve sharply backwards, terminating in a hook-like 
process at the extremity of which is the gonothecal mouth. 
The type of this species was found at Kerguelen in 1874. 
H{ALECIUM TENELLUM. 
Halecium tenellum, T. Hincks, Brit. Hyd. Zoophytes (1868), p. 226, pl. xlv., fig. 1. 
Localities. —W.Q., McMurdo Bay, February 20th, 1902;—20 fms. W.Q., Flagon 
Point, January 17th, 1903; 10-20 fms. W.Q., Flagon Point, February 23rd, 1903. 
W.Q., off cable, February 17th, 1904. W.Q., D net, June 15th, 1902. 
This widely distributed little //alecitum appears to be fairly common in 
McMurdo Bay. It is found on sea-weed, Alcyonium paessleri, on Halecium arboreum, 
and on other hydroids. ; 
Hydrosome.—The delicate little colonies are about 10 mm. in height and 
spring from a creeping hydrorhiza. The hydrocauli are monosiphonic, irregularly 
