185 



numbers (figs. 107 /, 108 A). More than two cells may sometimes fuse together. The 

 cells of the basal layer are low, and the same may also be the case with the under- 

 most cells in the erect filaments, while those of the middle and the upper part 

 of the filaments may reach a length of up to 2,5 times the breadth. The erect 

 filaments have almost the same breadth in their whole length, frequently, however, 

 they are a little thicker towards the base, and the uppermost cell may 'be a little 

 thicker than the second from the top. The tilaments are rather firmly connected, 

 but not or only to a slight degree united by a gelatinous collode. In the undermost 

 part of the frond 

 fusions may 

 sometimes take 

 place between 

 contiguouscells 

 of different fila- 

 ments, as in the 

 following spe- 

 cies. The sur- 

 face is cove- 

 red with a ra- 

 ther firm out- 

 er wall. Each 

 cell contains a 

 calotte - shaped 

 chi'omatophore 

 and a small 

 nucleus, little 



susceptible to staining reagents. The frond is, at all events in some cases, poly- 

 stromatic to the border (fig. 108 F). 



Here and there some of the erect filaments terminate in hyaline hairs; these 

 occur in varying quantity, usually solitary. They are fairly rich in protoplasm. 

 The subjacent cell is somewhat lengthened, conical (fig. 107). 



The sporangia arise from the terminal cell of erect filaments. They reach the 

 surface of the frond and are originally, like the vegetative cells, covered with a thick 

 outer wall (fig. 108). The first wall is inclined, the two following perpendicular to 

 it (figs. 107 G, 108 E). After evacuation of the sporangium a new one may some- 

 times be formed from the subjacent cell within the emptied sporangial wall (fig. 107 F). 



In specimens dredged in the Little Belt in July 1915 I found very short-celled fila- 

 ments which were supposed to be auxiliary-cell filaments, though carpogonia were 

 not found. They arose from erect filaments, which in a smaller or greater extent 

 of their length consisted of low, disc-shaped cells, the undermost and one, or more 

 rarely two or three, of the uppermost cells showing the ordinary length. The short 

 cells were of a feebler colour than the other cells; they resembled the auxiliary- 



Fig. 107. 



Criioriopsis danica. A—H from M. A — D, vertical sections of frond, in B a young hair, in C, 

 a more developed hair, in D, fully developed erect filaments, a little swollen at the top, E, 

 unripe sporangium. F, new sporangia formed within emptied sporangial walls. G, H, ripe 

 sporangia. /, K from MK. /, liasal layer from the face showing fusions. K, erect fdament 



ending in hair. 390 : 1. 



D. K. D Viilciisk. SelsU Skr., 7. liickke, naturvidensk. ot! matliem. Afil. VII. 2. 



24 



