176 THE MARINE BOTANIST. 



December, plants with both kinds of fruit are 

 thrown up. Specimens with tetraspores have not 

 been collected at Plymouth. 



Grows in deep water on shells, &c., in muddy 

 harbours and estuaries. Discovered in 1847 by 

 Dr. John Cocks at Bovisand, near Plymouth, and 

 at Mount Edgecombe a few days later by the Rev. 

 W. S. Hore. Minehead, Somerset, August, 1848, 

 noticed the tetraspores on October plants ^ I. G. A 

 single plant with tetrasporic fruit dredged in Cork 

 Harbour by Mr. Carroll, 1851. 



RHODYMENIA. 



Name signifying red membrane. 



Frond flat, membranaceous or slightly leathery, 

 quite ribless and veinless, cellular. Fructifica- 

 tion : 1, convex tubercles (coccidia) containing 

 minute spores ; 2, tetraspores either scattered 

 or forming cloudy patches. 



