REPORT ON THE HYDROLDA. 
13 
Halecium fastigiatum, n. sp. (PI. XV. figs. 2, 2a). 
Trophosome . — Hydrocaulus with the main stem and principal branches fascicled, 
becoming monosiphonic and slender towards their distal extremities ; ramification profuse 
and irregular, with the branches given off in different planes and at a high angle. 
Gonosome . — Gonangia (male) springing from the side of the basal segment of the 
hydrophores, sessile, compressed goblet-shaped, deep. 
Locality . — Station 135c, off Nightingale Island, Tristan da Cunha; depth, 110 fathoms. 
This is a slender and flexile species. The specimens are but fragmentary and 
destitute of hydrorhizal extremity, and the largest has a height of upwards of two 
inches. The branches, which like the gonangia spring from the fixed basal segment 
of the hydrophore, are given off at an acute angle and become directed in various planes. 
The internodes are of moderate length. 
The hydrophores usually present two or three superimposed segments, but are 
often formed alone by the fixed lateral process of the stem, which then carries 
the hydranth directly. The segments are of variable length and the limbus is well 
developed. The wreath of brilliant points just within the margin is distinct. The 
hydranths are large and were well preserved in the specimen, where they might be 
observed in various states of extension. 
The gonangia are large, their height being nearly twice that of an internode. They 
spring, as is usual in the genus, from the basal segment of the hydrophore. When viewed 
in the plane of the hydrophores they present the outline of a deep wide-mouthed goblet, 
slightly everted towards the rim, and narrowed at their point of attachment without 
forming a distinct peduncle. When viewed in a plane at right angles to this they are 
seen to be much compressed. 
The gonangia present in the specimen were those of a male colony. The blastostyle 
carried a single sporosac, which projected for some distance through the orifice of the 
gonangium. 
Halecium dichotomum, n. sp. (PI. VI. figs. 1-4). 
Trophosome. — Hydrocaulus consisting of jointed stems which branch dichotomously 
and are continuous at their proximal ends with a plexus of branching and inter- 
communicating tubes ; internodes of stem long and cylindrical, branches given off 
close to the distal ends of the internodes. Hydrophores either direct continuations of 
the internodes, or springing from the sides of the tubes which form the basal plexus, 
nearly cylindrical, with a few annular rugae at the base, and with very narrow, scarcely 
everted limbus. 
Gonosome. — Gonangia (female) springing each by a short peduncle from the sides 
