REPORT ON THE HYDROIDA. 
75 
internocles of various lengths. Hydrothecae borne both by stem and pinnae, deep, 
tumid below, slightly narrowing upwards, those of each pair adnate to one another 
for nearly two-thirds of the height of their opposed sides, then diverging and terminating 
in a circular orifice which is directed laterally, and is surrounded by a thin, membranous, 
expanded lip. 
Gonosome . — Gonangia fusiform, contracting below into a very short, narrow peduncle, 
and terminating distally in an even circular orifice. 
Locality . — Station 163a, off Twofold Bay, Australia; depth, 150 fathoms. 
Hypopyxis labrosa attains a height of about four inches. The pinnae are given off 
at a moderate distance from one another along nearly the whole length of the stem. 
Each is supported on a short cladophore which springs from the side of the stem between 
two pairs of hydrothecae. Every pinna commences with a short proximal segment which 
is destitute of hydrothecae, and is united to the remainder of the pinna by a very oblique 
splice-like joint. The orifice of the hydrotheca is surrounded by a membranous expanded 
lip. This is very thin, and would seem to be easily lacerated and destroyed, for it was 
only occasionally preserved in a sufficiently perfect state in the specimens examined. 
The joints which separate the internodes of the pinnae from one another are very oblique 
and splice-like, and the number of pairs of hydrothecae borne by each internode varies 
from five to seven, or perhaps more. The hydrothecae are all brought to one side (the 
front) of the internode, the opposite side remaining uncovered. 
The cup-like appendages of the base of the hydrothecae have, when viewed in front, the 
form of a wide bell, but when viewed laterally are seen to be compressed. They measure 
about one-sixth of the height of the hydrotheca. Each hydrotheca carries two, one on 
the front of its base near its junction with the opposite hydrotheca, the other on a point 
of its base which lies diametrically opposite to this. 
The gonangia spring from the front of the pinna in the intervals between the pairs 
of hydrothecae, and correspond in height to about three pairs of hydrothecae. 
Staurotheca, n. gen. 
Name from oravpos, a cross, and OqKq, a receptacle, in allusion to the decussation of the hydro- 
thecae. 
Generic Character. Trophosome . — Hydrocaulus carrying opposite hydrothecae, 
which are arranged in decussating pairs. 
Gonosome . — Gonangia simple capsules springing from the hydrocaulus, and 
destitute of marsupium. 
The genus Staurotheca has close affinities with Sertularia, from which, however, 
it is distinguished by its decussating hydrothecae. These are so disposed that the 
