596 
In 1907 (Studien, p. 127) Kyrın described a new parasitic Alga, Choreocolax 
Cystocloni, growing on Cystoclonium purpureum. It forms irregular globular bodies, 
1—4 mm in diameter, yellow-white, often with a tinge of pink; they have a cortex 
built up of radial cell-rows and an inner tissue of isodiametrical or irregular larger 
cells, and between them and springing from them long branched cell-rows which 
penetrate from the base of the parasite between the cells of the host. The parasite 
usually occurred abundantly on one.and the same individual of Cystoclonium; it 
was always sterile. The supposed parasite bears so much resemblance to the 
tumours here treated, that the question arises if they might possibly be identical 
with them. Judging from Kyrın’s description, the outer appearance is the same, 
and there seems too to be much accordance as to the anatomical structure, though 
the hypha-like cell-rows show some disagreement; but the occurrence of these ele- 
ments seems to be rather variable. I have not observed stages like that shown in 
Ky in’s fig. 29 a, which is said to represent filaments of the parasite penetrating 
between the cells of the host. Altogether it must be said that the parasitic char- 
acter of the bodies described by KyLiN cannot be said to be proved. Considering 
further the fact that the supposed parasite was always sterile, it seems highly 
probable to me that they are identical with the tumours here described, and that 
like these, they are merely luxuriancies caused by some unknown agency. It should 
be stated that Kyrın did not mention bacteria in the tissue of the tumours. 
The tumours have been met with repeatedly in the environs of Frederikshavn, 
particularly east of Deget (Boye Petersen), off Feggeklit in the Limfjord, in Lille 
Middelgrund in the eastern Kattegat and near Ostindiefarergrund in the southern 
Kattegat. 
Euthora J. Agardh. 
1. Euthora eristata (L.) J. Agardh. 
J. Agardh, Nya alger fran Mexico. Ofvers. af K. (svenska) Vetensk. Ak. Förhandl. 1847; id., Sp. g. o. 
Vol. II, pars II, p. 385, 1851; N. Wille, Morph. og physiol. Studier over Alger. Nyt Mag. f. Natur- 
vidensk. Bd. 32. II. 1891, p. 107 ff, Tavle II; Kylin, Entw. Flor. 1923, pp. 36—37. 
Fucus gigartinus L.? Oeder, Flora Danica, Tab. 394. 1768. 
Fucus cristatus L., Turner Fuci I. 1818, Tab. 23, p. 48. 
Spherococcus cristatus Agardh Synops. 1817, p. 29; Lyngbye, Tent., 1819, p.13, Tab. 4 D. 
Rhodomenia cristata Greville Alg. Brit. 1830, p. 89. 
Rhodymenia cristata Harvey, Phyc. Brit. III, tab. 307, 1851. 
Callophyllis cristata Kützing, Tab. phyc. 17, tab. 93, 1867. 
This pretty little subarctic Alga has only been met with in a few places in 
the eastern Kattegat at 22—25 metres’ depth. It will only be briefly mentioned 
here, as I have no new observations on the morphology and the development. The 
fronds are rather narrow, mostly alternately pinnate, more rarely secund or subdi- 
chotomous and flabelliform. The structure of the frond has been described by WILLE 
and Kyrın. As shown by these authors, the segments of the frond terminate in 
