1£>19] Setchell-Gardncr: Myxophyceac 29 



ation showed that the colonies were unusually variable in shape and in 

 size, some capping tlic filaments, others completely surrounding and 

 obscuring them for some distance, and still others small and widely 

 separated. Material scraped from the filaments and magnified 

 revealed a surprising variation in the shape and size of the vegetative 

 cells, as well as of the gonidangia. Among the collection one could 

 select cells in both vegetative and reproductive conditions which would 

 conform to the description, in shape and in size, of each of several 

 well known species ; but since there is such perfect gradation in 

 lengths and in widths, both in purely vegetative cells and in tlie 

 gonidangia, ranging in size of mature cells from 6/x to 4()/x wide in 

 the upper parts, and from 40/a to 120/a long, it is impossible to segre- 

 gate them into species. Considered as a species D. protca represents 

 the largest known species of Dermocarpa, and has the greatest range 

 of variation in size and in shape of the cells. Plate 4, figs. 4, 5 

 represents some of these found among the gonidangia. 



Dermocarpa protea is an excellent example of the formation of 

 gonidia by successive and progressive divisions of the gonidangia to 

 form gonidia. This method is represented in the gonidangia irre- 

 spective of shapes and sizes, and is another evidence in support of 

 their all belonging to a single species. 



Kirchner (1898, p. 58) in his key to the genera places Dermocarpa 

 in the group which produces the gonidia by simultaneous division of 

 tlic protoplast. In Cytological Studies in Cyanophyceae (1906, p. 281) 

 Gardner expressed the opinion that Dermocarpa fucicola Saunders 

 produces gonidia in this manner. We have since examined authentic 

 material of that species and, although the gonidangia are very sparse, 

 it appears to form tluiii by simultaneous division; l)ut liaving exam- 

 ined other collections from our coast which seem to be of the same 

 species, judging from the shape and size of the cells, which clearly show 

 that the formation of gonidia is by successive divisions of the proto- 

 plast, some doubt may still be entertained as to which method D. fuci- 

 cola follows. This subject must have more careful stud.v and may 

 prove to be a more stable character than shapes and sizes of cells 

 upon which to establish species. 



Dermocarpa prasina (Reinsch) B. and Th. has been credited to our 

 coast by Saunders (1898, p. 397) as occurring on " Sphacelaria race- 

 mosa arctica" and " Sphacelaria cirrhosa" and extending from Puget 

 Sound to the Shumagin Islands in Alaska. It seems to us unlikely 

 that this species should l)e represenlcd in these waters, but we have 



