246 BRITISH SEA-WEEDS. 



of a bright grass-green colour ; but this is changed to a 

 glossy brown by the process of drying. It is reputedly 

 rare, but this is most probably due to the fact that it is 

 not easy to find its unobtrusive fronds, and that they are, 

 therefore, frequently overlooked. 



Genus CVI. BBYOPSIS. 



Boot fibrous. Pronds growing in tufts, erect, each con- 

 sisting of a single, branched, one-celled, cylindrical filament, 

 with membranaceous shining walls, and imbricated or pinnate 

 branches and branchlets. Zoospores formed from a granular 

 glutinous endochrome within the cell, from whicb they 

 escape at maturity through apertures in its wall. — Bbtopsis, 

 from the Greek hryon, moss, and opsis, form. 



Representatives of this genus are widely dispersed in 

 all latitudes, and in consequence many species have been 

 described. It is, however, doubtful whether some at 

 least of these are not merely varieties of B. plumosa, 

 changed more or less in form by the circumstances 

 of their growth. Dr. Harvey, in his ' Nereis Boreali- 

 Americana,' expresses his belief that they are, and 

 adduces strong evidence in support of his opinion. 



Bryopsis plumosa. The feathery Bryopsis. 



Fronds growing in tufts or singly, from two to four inches 

 high, once or twice pinnate, the lower part of the stem, of 

 all the divisions of the frond, naked. 



The light feathery form of the fronds of this species, 

 and their bright green colour, which is preserved, and 

 becomes lustrous when they are dried, entitle it to rank 

 among the most beautiful of the green series of sea- 



