6 
of growth is Hcilecium curvicaule, which bas been described under 
various names according to the sbape of the colony: H. curvicaule 
v. Lorenz, H. mirabile Schydlowsky, H. repens Jåderholm. Tbe 
Greenland colonies of Halecium minutum witb compound stem must 
be regarded from tbe same point of view. Several rhizocauli cover 
tbe support (hydroid colonies, especially Halecium muricatum ), sen¬ 
ding, out now and then small, sparingly branched stems, as is usually 
tbe case in this species; sometimes, however, a number of tbe 
rhizocauli seem to run together and leave tbe support as a bundle 
of tubes, a compound stem. This stem can divide into compound 
branches, consisting of several tubes, tapering in tbickness (consisting 
of fewer tubes) towards the distal end. Moreover small simple 
branches issue, exactly vvith the shape of the small, slightly branched 
stems of a coramon H. minutum , bearing a number of hydrothecæ 
which do not differ in any respect from tbe common H. minutum. 
On the stems and branches several of the large characteristic female 
gonothecæ are present, thus no mistake as to tbe identification 
being possible. — Since the colonies in question are growing on hy- 
droids, most of them on H. muricatum, one could think, perhaps, 
that the compound stem mentioned was only a number of rhizo¬ 
cauli of the H. minutum growing on a little branch of the H. 
muricatum. Further investigations have shown, however, that this 
is not the case; all the tubes of the compound stem belong to H. 
minutum and issue from the rhizocauli running over the surface of 
the stem and branches of the muricatum- colony. 
In 1909 Broch described and figured (1909 b, p. 153, text- 
figs. 13, 14) some colonies of a small species of Halecium very 
much alike H. minutum , but the colonies were sterile, and accor- 
dingly they could not be identified with certainty. On some of the 
colonies Broch saw rows of hydrothecæ (pseudohydrocauli) very much 
like the pseudohydrocauli of the species described by Jåderholm 
(1908) as H. telescopicum Allman; but as this species has a com¬ 
pound stem, Broch would not refer his colonies to the same species. 
Now we have seen that H. minutum may appear with compound 
