81 



As two-thirds of the species described below are new, and as I have several 

 new observations on most of the formerly described species, it might be useful to 

 make here some general remarks on the genus Chantransia, based on the obser- 

 vations communicated below. 



As shown by Bornet (1904), the structure and development of the basal por- 

 tion of the frond within the genus Chantransia offers considerable differences which 

 can be used in subdividing the genus. I fully agree with this excellent phycologist 

 who by his small but important paper has largely contributed to the classification 

 of this genus. If my classification does not always coincide with that of Dr. Bornet, 

 it depends on the fact that I have not found representatives for all the subdivisions 

 of Bornet in the Danish waters, and that I have found new species which do not 

 fall under these groups. I may now give an account of the types found by me. 



In some species the germinating spore is a globular or hemispherical basal 

 cell which keeps its form and divides only on branching. This cell is fastened to 

 the substratum by a cementing substance staining intensely blue by Mayer's Hae- 

 malum'. In some cases it gives olf only free filaments (first group), in others it 

 also produces endophytic filaments from its under side (Bornet's second group, of 

 which no representative is mentioned below). In Ch. efflorescens (fig. 61) and Ch. 

 Thuretii (figs. 30, 31) the hemispherical basal cell gives otf an erect filament and 

 several radiating, creeping, epiphytic filaments which later unite to a pseudoparen- 

 chymatous disc giving off a number of erect filaments. During this development 

 the original basal cell becomes indistinguishable amongst the other cells of the 

 basal disc. I believe that the basal part of the frond probably develops in a similar 

 manner in some other species, the germination of which has not been observed 

 (Ch. attenuata, stricia, Dainesii). In a small group of species (Ch. polyblasta (fig. 43) 

 and Ch. humilis (fig. 44)), to which may be added the partly endophytic species 

 Ch. Dumontice (fig. 52) and Ch. cytophaga (fig. 50), the germinating spore is divided 

 before ramification by a vertical wall into two cells of equal size each growing out 

 in a creeping filament, which branches and forms a filamentous basal structure; 

 in the central part of this the filaments may later fuse together, while a large 

 number of relatively short erect filaments are given off from their upper side. In 

 Ch. virgatula (incl. secundata) the germinating spore is usually divided by 3 excen- 

 tric walls into 4 cells forming a parenchymatous disc, which for some time keeps 

 this character during continued divisions of the cells, while later on some of the 

 marginal cells may grow out into creeping filaments (figs. 37 — 41). In Ch. leptonema 

 the development begins in the same manner, but the parenchymatous stage is very 

 short, the disc at an early stage growing out into long creeping filaments (fig. 48). 

 In Ch. Macula the basal disc behaves in a somewhat similar manner as in Ch. vir- 

 gatula, but the erect filaments are much reduced or wanting, the sporangia being 



' This substance attains an extraordinarily great development in Ch. microscopica var. collopoda 

 Rosenv. (Deux. iMem. Alg. mar. Groenl., Medd. cm Granl. XX, 1898, p. 11), which, however, does not belong 

 to Ch. miscroscopica Nxg. but ought to be regai'ded as a distinct species, Ch. collopoda Rosenv. 



D. K. I). VideiisU. Selsk. Slu-., 7. Kiekke, naturvitlensk. og inatliem. Aid. VII. 1. 11 



