0SCILLAT0R1ACE.E. 285 



growing in star-like tufts on the branches of filiform algae ; 

 tube rather thick, containing separate masses of dull, blu- 

 ish-green endochrome. 



This very minute parasite is widely distributed, both on 

 our own shores and on those of other countries. 



Calothrix luteola. The yellowish Calothrix. 



Threads about one-tenth of an inch long, flexible, blunt, 

 transparent, of a pale yellowish colour, growiug singly or in 

 small tufts on filiform algse ; tube more or less filled with 

 faintly annulated, pale green endochrome. 



This species is very minute, and in consequence very 

 difficult to collect. "When found, it must be examined 

 under a microscope of high power, or its structure and 

 characters will not be properly revealed. The re- 

 corded observations of different authors do not agree; 

 but the discrepancy has probably arisen from some of 

 the specimens examined being young and others mature, 

 or in a state of incipient decay. In the former, the 

 threads, being full of endochrome, w^ould be opake, while 

 in the latter, the sporidia having been discharged, they 

 would be empty and transparent, and this is the point 

 that is in dispute. 



Calothrix scopulorum. The rock Calothrix. 



Threads about one-tenth of an inch high, simple, bent 

 or curled, awl-shaped, tapered to a point, interwoven, grow- 

 ing in closely-packed, velvety patches, on rocks ; tube filled 

 with dull, yellowish-green endochrome, which is more or 

 less distinctly annulated. 



This species grows near high-water mark, and coats 



