F. Borgesen: List of species. 427 



The above mentioned non-colouring of the wall of Rhizoclo- 

 nium with Chlor-Zinc-Iodine is of no use as a means of distinction, 

 as the wall of Chætomorpha, too, does not show the common 

 reaction of cellulose. 



Finally I agree absolutely with Stockmayer when he recom- 

 mends to study these plant upon living material. 



Among the fixed forms I think the two forms mentioned be- 

 low may be distinguished. 



23. Rhizoclonium Kochianum Kütz. 



Fig. 406 a, 6, c, shows a form in which the cells are from 

 nearly as long as broad up to 2V2 times as long; their diameter 

 varies from 13 to 20 /j. in length. 



The zoosporangia are a little thicker, about 25 fx. 



Another form is figured in Fig. 406 d, e, /, g. It is a little 

 thicker than the above described plant, its vegetative cells reach- 

 ing a breadth of about 20 //, the length of the cells up to 62 ;/. 

 The zoosporangia are about 35 // thick. 



St. Jan: Christiansfort. 



24. Rhizoclonium Kerneri Stockm. 



Some other of the fixed forms I prefer to refer to this species 

 which is characterized by its somewhat longer cells. 



Fig. 407 a, b, c shows one form whose vegetative cells are 

 about 10 fjt thick and 40 /i long. It is fixed to the rocks by a long 

 rhizoid formed by throughgrowing of three cells. 



The zoosporangia are often a little narrowed in their middle, 

 about 13 fj. thick. 



Another form with somewhat shorter cells is figured in Fig. 

 407 d, e. The vegetative cells are about 12 pi broad and two to 

 four times as long. 



St. Jan: Christiansfort. 



25. Cladophora uncinata Bergs. 



26. — corallicola Borgs. 



27. — fuligiuosa Kütz. 



28. — utriculosa Kütz. 



KüTziNG, Phycologia generalis, p. 269; Species Alg., p. 393; Tabulæ 

 Phycologicæ, vol. 3, tab. 94, fig. 1. Hauck, Meeresalgen, p. 464. 



