CALOTHRIX. 243 



itself in a distinct genus, and perhaps this would have been 

 the correct course ; it is, however, more naturally associated 

 with the genus Toiypothrix than with Scytonema. It forms 

 little tufts two or three lines in height. 



28. CALOTHRIX. 



Char. Filaments of equal diameter, branched by apposition. 

 Derivation. From KO\OS, beautiful, and 0/o^f, a hair. 



1. CALOTHRIX MIRABILIS. 

 Plate LXIX. Fig. 1. 



Char. Filaments tufted, aruginous, black, articulated. Striae 

 distant about the half of a diameter from each other, dis- 

 tinct. 



Conf. mirabilis Dillw. t. 96. Calothrix atroviridis Harv. 

 in Manual, p. 159. ; Harv. in Hook. B. Flora, p. 369. 



Hab. On mosses and in small streams, rare. Stream 

 which runs through the wood at Penllegare, near 

 Swansea : Dillwyn. C. atroviridis in spring wells, near 

 Penzance : Mr. Ralfs. Aberdeen : Dr. Dickie. 



Having had opportunities of examining, through the kind- 

 ness of Mr. Dillwyn and Mr. Harvey, authentic specimens of 

 Conf. mirabilis and Calothrix atroviridis, I have no hesita- 

 tion in declaring that the two plants are identical. There 

 is a close resemblance between C. mirabilis and Lyngbya 

 copulata, which species ought not to be far removed from each 

 other in a natural arrangement. 



R 2 



