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 Tolypothrix than with Scytonema. It forms 

 little tufts two or thi*ee lines in height. 



28. CALOTHKIX. 



Char. Filaments of equal diameter , branched by apposition. 

 Derivation. From KaXos, beautiful^ and Qpi^, a hair. 



1. Calothrix mirabilis. 



Plate LXIX. Fig. 1. 



Char. Filaments tufted, (Bruginous, black, articulated. Strias 

 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 



