383 
The frond reaches a length of up to 14 cm. Tetrasporangia have been met with 
repeatedly in May to July, antheridia once in May, cystocarps only once in a dubious 
specimen from the southern Kattegat, gathered in July. The tetrasporangia were at 
any rate often cruciately divided. 
Localities. Kn; Skagen, south side of Grenen. — Ks: (?)EJ, Lysegrund; OT, Hastens Grund. 
— Sa: PG, W. of Hatterrev; Hofmansgave (Lyngbye). — Lb: FZ, Kasserodde; Baaring, harbour; Dyre- 
borg. — Sf: CV, Billes Grunde; DZ, Egholms Flak. — Sb: UU, Snode Rev. 
11. Ceramium atlantieum Henn. Petersen. 
Henning Petersen 1911 p. 112. 
Dr. Petersen refers to this species a specimen collected in April 1906 in the 
harbour of Skagen then unfinished. It has formerly (1908) been referred to C. fru- 
ticulosum f. rubroides. It was 13 cm high, but still sterile. C. atlanticum has till now 
been recorded from Iceland and the Feerées. 
Locality: Kn: Harbour of Skagen. 
12. Ceramium Boergesenii Henn. Petersen. 
Henning Petersen 1911, p. 108, fig. I, pl. II fig. 8. 
C. fruticulosum f. rubroides Henn. Petersen 1908 pp. 73, 93 ex parte, pl. IV fig. 1. 
Dr. PETERSEN has found that some specimens from the Limfjord, formerly 
referred to C. fruticulosum f. rubroides, must be referred to C. Boergesenii which was 
described on the basis of specimens from the Fxröes, and which is easily recognis- 
able by the characteristic small-celled cortication. The species was met with near 
low-water mark in July and September, in all the places with tetrasporangia, in 
one place with cystocarps in July. The collected specimens are 7—9 cm long. 
Localities. Lf: Thisted; Nykøbing; Hals. — Kn: Two specimens from Nordre Ronner must 
probably, according to Dr. Petersen, be referred to this species though the cortication is not quite typical. 
13. Ceramium scandinavieum Henn. Petersen. n. sp, 
C. fronde regulariter dichotoma + corymbosa fastigiata 
apicibus incurvatis, in partibus basalibus et intermediis 
cortice continuo, in partibus superioribus interstitiis pellu- 
cidis semper brevibus instructa. Zonæ superiores ab initio 
adproximatæ, marginibus vix crescentibus, deinde ab 
utroque margine inprimis a superiori crescentes. Cellulæ 
marginis inferioris semper latæ in seriebus longitudinalibus 
ordinatæ. Cystocarpia in ramis principalibus; antheridia in 
soris; tetrasporangia verticillata in partibus nodalibus parum 
erumpentia. — Color in individuis danicis subruber, in indi- 
Fig. 324. 
Ceramium scandinavicum. Cortical 
viduis ex regionibus borealibus fusco-rubiginosus. (Fig. 324). band. H. Ptrsn. del. 330 : 1. 
19* 
