HYDROID ZOOPHYTES. 19 
Hydrosome.—A solitary zooid. The hydrocaulus is about 8 mm. in height and 
about 2 mm. in diameter for the greater part of its length. At the base it is much 
thinner and gives off numerous hydrorhizal filaments (fig. 18, Arh. 7.) for attachment 
to the sponge spicule débris. It is covered throughout its length by a thin chitinous 
perisare with transverse striations. 
The hydranth is naked, about 6 mm. in length, and spindle-shaped, thickening 
gradually from the hydrocaulus, and then gradually tapering to form the conical 
hypostome. The distal half of the hydranth bears numerous short, thick, scattered 
conical or hemispherical tentacles (fig. 18, ¢.) the largest of which are situated just 
above the thickest part of the hydranth. 
Gonosome.—-No gonophores are present. 
Although we are unable to give a generic or specific name to this specimen, we 
are anxious to record the existence of a member of this family in the Antarctic Sea. 
Hartlaub, in his summary of the Southern Hydroids, does not mention the family at 
all, but Jiiderholm (13: p. 2.) records the occurrence of Jf austro-georgiae from 
South Georgia. 
FAMILY SERTULARIIDAE. 
SERTULARELLA SPIRALIS. 
(Plate III., figs. 19, 20.) 
Locality. W.Q., No. 10 hole, July 3rd, 1903; 130 fms. 
Several fine colonies of this species were obtained from this hole at the date 
given above. It is perhaps noteworthy that no other specimens were obtained from 
any other localities, although at this particular spot the species seems to have 
been so abundant. Unfortunately, all the colonies were torn away from their 
attachments, so that in some particulars our description must be imperfect. 
Hydrosome.—The slender monosiphonic hydrocaulus is 250 mm. or more in 
height. It is bent alternately right and left at intervals of 5 mm., and at each 
geniculation two branches are given off from the major angle. Each of these 
branches is about 40 mm. in length, slightly geniculated and pinnately branched, 
the pinnules arising as before from the neighbourhood of the angles. Their internodes 
are about 2°5 mm. in-leneth. In some cases one or both of the branches themselves 
are elongated to form an axis similar to the main axis and give rise to secondary 
branches similar to the primary branches. 
The general effect of this method of ramification is to give the appearance of 
a spiral form similar to that so characteristic of the genus //ydra/limania. 
The pinnules vary in length up to 30 mm. and are divided into a series of 
internodes by geniculations, but these internodes are not all of the same length 
(0°6-1°0 mm.), increasing somewhat in length in the distal parts. Proximally the 
nodes are not very clearly marked. 
bo 
ic] 
bo 
