567 
diplobiontic Florideæ. The frond and the primary nemathecial filaments make 
the first generation, corresponding to the gametophytic generation of the diplobiontie 
Florideæ, though sex organs are not produced, whereas the cell-filaments springing 
from the generative cells, the secondary nemathecial filaments and the mono- 
sporangia, belong to the second, sporophytic generation arising from the first without 
any process of fertilization. As no fertilization takes place and no other nuclear fusion 
has been observed, it must be supposed that no diploid nuclei occur, and it is in 
good accordance herewith that the number of chromosomes seems to be the same (4) 
in the two generations, and that the formation of the monospores takes place 
without chromosome reduction. The monosporangia must most probably be 
considered as reduced tetrasporangia which have 
failed to be divided owing to the wanting Sr 7 
reduction division of the nuclei, and the nema- EIER 
thecia of Ahnfeltia would then be comparable to RS 
the nemathecia of Phyllophora Brodiei. In the x 
discussion in my previous paper (1931, p. 24), 
yet another interpretation has been taken into 
consideration, namely that the secondary nema- 
thecial filaments might be considered as gonimo- 
blast cell-rows. The whole complex of secondary A B 
nemathecial filaments would then be a compound Fig 563 bis 
cystocarpium and the monospores must be  Ahn/éltia plicata, f. tenuior, A, from NU, off 
Bovense, Store Belt. B, from aV, east of Samsø. 
regarded as carpospores. This interpretation LAB 
seems, however, to be less probable than the 
first. Comp. SvepELius, Nuclear Phases and Alternation in the Rhodyphyceae. 
Beih. z. Botan. Centralbl. Bd. 48 (1931) Abt. I, p. 57. 
The systematic position of the genus Ahnfeltia remains doubtful, as sex organs 
and cystocarps are wanting. The presence of nemathecia perhaps warrants its 
classification among the Gigartinacecæ. 
la 
) 
Ahnfeltia plicata occurs in all the Danish waters except the Baltic Sea around 
Bornholm (Bb), from a little below low-water mark to 10 metres’ depth, always 
growing on stones. 
Localities. Ns: Thyboren, on a groin. — Sk: Hanstholm, washed ashore; 13 miles SW by 
W !/2W of Rubjerg Knude light-house, 14 m, sand, a small specimen (C.A.J.); Hirtshals, the mole, stones 
west of the mole, Emstenen. — Lf: Common on stony ground from Kobberod, 2—4 m, to Hals mole 
(F. Børgesen). — Kn: Krageskovs Rev; Hirsholmene; Strandby; stony reefs around Frederikshavn; 
several localities north of Læsø; Nordre Ronner; TL. — Ke: Søborg Hoved Grund and Vesterlands 
Grund at Gilleleje; Gilleleje harbour. — Km: Vesterø harbour Læsø; XF South of Læsø; BO off Stens- 
nes; Gerrild Bay (Lyngbye); KG off Nordstrands Klint, Anholt. — Ks: Grenaa harbour; NB, Havknude 
Flak; Jessens Grund; EJ and HQ, Lysegrund; Hesselo (Lyngbye); Lynæs harbour; GG, Sjællands Rey 
Sa: Common on stony ground. — Lb: Common from Bogense harbour to Brandso, Linderum, at Sonder- 
balle Hoved and dG, Hesteskoen. — Sf: CC, Hornenæs: CA near Faaborg; Ærø (Kjærbølling); Skaaruper 
(E. Rostrup). — Sb: Numerous localities along the coasts from 1 to 7 metres’ depth, abundantly e.g 
