217 



Lithophyllum Lcnormandi (Aresch.) Rosanoff, Rech. anat. p. 85, pi. V, fig. 16 et 17, pi. VI, fig. 1, 2, 3, 5. 

 (Fig. 5 is said in the text to represent L. Lencirmandi, while in the explanation of plates it is attri- 

 buted to L. lichenoides). Hauck, Meeresalg. p. 267, Taf. Ill fig. 4; Stromfelt, Algveg. Isl. kuster, p. 21, 

 tab. I, fig. 9—10. 



Lithothamnion squamiilosum Foslie, Norw. Forms of Lithoth p. 155, Tab 19 fig. 24 — 26. 

 Squamolitlion Lenormandi (Aresch.) Heydrich, Die Lithoth. von Roscoff. Ber. dent. hot. Ges. 1911, 

 p. 26, Taf. II. 



This widely spread species has been met with in almost all the Danish waters. 

 It is particularly characterized by its thin reddish-violet crust with a lobed, whitish 

 border, by its hypothallium composed of densely joined filaments, and at all events 

 in the typical species, by the 

 densely crowded concep- 

 tacles. 



As pointed out by Mme 

 Lemoine, the hypothallium 

 is composed of more densely 

 joined filaments than in the 

 other crustaceous species. 

 According to this author, the 

 number of horizontal fila- 

 ments in a vertical section 

 is usually 7 — 8; in thicker 

 crusts it may be greater (fig. 

 133 B), in thinner it may be 

 only 3-4 (fig. 133 A, C). In 

 horizontal sections through 

 the hypothallium transverse 

 fusions are frequently seen 

 (fig. 133 D). Mme Lemoine states that the filaments of the hypothallium "se relevent 

 d'une facon tres brusque pour constituer les files du perithalle". This, however, is, 

 in my opinion, not characteristic of the species, as will be seen in my tig. 133. 

 The cells of the hypothallium which, according to Muie Lemoine, are 3 — 4 c< thick, 

 I generally found somewhat thicker, 3,5 — 6 m, in specimens from the Limfjord 5 — 6 m, 

 the length 12-18,5 /j. The cells of the perithallium I found 4— 6/^ thick, 4—13/^ 

 long. In the perithallium also numerous transverse fusions occur, but as the cells 

 are closely joined, the fusion canals are very short. 



The sporangial conceptacles are very crowded, in particular in f. typica; they 

 measure 200—300/^ in diameter. The flat roof is, according to Foslie, intersected 

 by 25 to 35 muciferous canals, which is in accordance with my observations; I 

 have, however, met with up to 45 canals. Transverse fusions between the cells of 

 the roof are frequently met with. The sporangia which are otherwise always tetra- 

 sporic, are also normally so in the Danish waters. Conceptacles with disporic 

 sporangia only, however, not infrequently occur (fig. 134 A). It might be suggested 



D. K. D. Viden.sk. Selsk. Ski-., 7. K;ekke, naturvidensk. og malhem. Af'd. VII. 2. 28 



Fig. 133. 



Lithothamnion Lenormandi. A, vertical ^section of border of frond, not 

 decalcified, made by grinding. B and C, vertical sections of tliick and tliiu 

 crusts, made by microtome tlirough decalcified fronds. D, liorizontal sec- 

 tion of liypothallium sliowing fusions. A 195 : L B—D 350:1. 



