103 
Zoophytes from Australia and New Zealand . 
nangia. As a general rule, the margins of the hydrothecae are 
smooth or furnished with two teeth ; the aperture of the go- 
nangium is surrounded by a rim or collar, and is frequently 
provided with an operculum. S. conferta , Kirchenpauer, is 
an example of a species whose gonangia are strongly marked 
with transverse wrinkles. 
It will be seen that this section, together with the genus 
Diphasia , Ag., comprehends nearly all the species formerly 
grouped under Lamouroux’s genus Dynamena. 
ft. The second group may be typically represented by 8. 
abietina , and includes forms with flexuous stems and flask¬ 
shaped alternate or subalternate hydrothecae. The gonothecae 
vary: in the type species and in S. flicula they are ovate and 
smooth; in S. pulchella , D’A. W. T., and in 8. elongata , La- 
mouroux, they are elongated, with long spines at the top. 
In S. flicula the hydrothecae are sometimes, though not in 
typical specimens, almost opposite. 
7 . The third section is well exemplified by S. cupressina, 
and contains comparatively few species. It may be defined 
as comprehending forms rather sparingly jointed, with alter¬ 
nate, tubular, deeply immersed hydrothecae. 
The forms belonging to this group approximate very closely 
to the genus Thuiaria. Indeed Prof. Allman, in a note to 
his paper in the twelfth volume of the Journ. of the Linn. 
fSoc., declares that both 8. argentea and S. cupressina are true 
Thuiarians. It seems to me, however, that S.fusca has more 
claims than any of them to be admitted among the Thuiariidae, 
both the hydrothecae and gonangia being strikingly and cha¬ 
racteristically of a Thuiarian type. The gonangia of the two 
preceding species show affinities to the second form described 
above, as exhibited by the last-named group. 
a. Type form S. pumila , Linn. 
Sertularia fexilis, sp. nov. (PI. XVII. figs. 1, la.) 
Trophosome. Hydrocaulus slender, attaining a height of 
about 8 inches. Pinnae alternate, given off at rather distant 
intervals. IIydrotheca 3 opposite, in pairs, subalternate on 
the main stem, one in the axil of each pinna, generally two 
pairs to each internode, tubular, distant, strongly divergent, 
those on the main stem less so than those on the pinnae. Aper¬ 
ture small, looking upwards, with one broad tooth on each 
side. 
Gonosome. Gonangia attached just beneath the base of a 
hydrotheca, on the main stem only, and confined to the upper 
