Halarachnion Kützing. 
1. Halarachnion ligulatum (Woodw.) Kützing. 
Kützing, Phycol. gener. p. 394, Taf. 74. 1; Berthold, Cryptonem. d. Golfes von Neapel, Leipzig, (1884) p. 22 — 
(an eadem species ?); T. H. Buffham, On the Antheridia etc. of some Florideæ. Journ. of the Quekett 
mieroscop. Club, Vol. V, ser. II p. 299, tab. 14 fig. 37—39. 
Ulva ligulata Woodward, Linn. Trans. III p. 54. 
Halymenia ligulata (Woodw.) Agardh, Spec. Alg., 1821, p. 210; Flora Danica tab. 2199 (1836) from Helgo- 
land; Harvey, Phyc. Brit. vol. I pl. 112, 1846; J. Agardh, Spec. g. o. Alg. Il,» 1851 p. 201; Bornet 
et Thuret, Notes algologiques, fasc. 1, Paris 1876, p. 44 pl. XIV, XV. 
I have only found a few small specimens of this species and have not sub- 
mitted them to closer examination As to the structure of the frond, reference may 
be made to the descriptive works and the quoted figures of Harvey, ‚KüTzıng, 
Bornet and THURET, which show that the inner part of the compressed frond consists 
of a slimy substance through which 
run widely spread medullary fila- 
ments, while the cortex is com- 
posed of two or three layers of 
cells. Colourless, rather thin hairs 
proceeding from peripheral cells 
were observed in specimens from 
Hirshals, but none in the other Fig. 78. 
examined specimens. BERTHOLD iranien ligulatum : from XJ. 4 and B, tips of slender shoots show- 
ing two filaments reaching the top. — C, surface of male plant. 630:1. 
(1. c. p. 7) did not observe them. 
In a small specimen from Herthas Flak I found in slender shoots two filaments 
running to the very end of the shoot, with the two apical cells at ihe same level 
and higher than those of the other filaments (fig. 78 B). In thicker shoots such 
structure is not to be found; the end of the shoot seems to be composed of a greater 
number of equal filaments. 
Sporangia have never been found in this species. 
The antheridia occur in the same specimens as the carpogonia (comp. BORNET 
et THURET, |. c. p. 45; BERTHOLD, |. c. p. 9). They have been briefly described and 
figured by BuFFHAM (I. c.). According to this author they arise from “a cell which 
produces four male cells above, and these emit the pollinoids, which are minute.” 
I found their arrangement less regular, their number, seen from the face, varying 
from 1 to 4 (fig. 78 C). As I had not occasion to examine them in transverse 
sections, I am not able to decide whether the small cells shown in the figure are 
really the antheridia (spermatangia) or possibly partly antheridia-producing cells 
(spermatangial mother cells after SvEDELIUS), as BUFFHAM's fig. 39 may suggest. 
The carpogonial branches are 4-celled, situated on the inner side of the cortex, 
and bent outwards (BorNET and THURET |. c. fig. 1). According to BERTHOLD and 
ScHMITZ, the fertilized carpogonium gives off in various directions a number of 
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