THE MARINE BOTANIST. 153 



surface ; composed of very slender, closely-packed 

 vertical filaments. Conceptacles immersed in the 

 frond; orbicular, depressed, containing tetraspores. 



HILDENBEANDTIA RUBRA.— RED HIL- 

 DENBRANDTIA. 



"On smooth stones and pebbles between tide- 

 marks, and in deep water. Common. Forms a 

 thin, membranous crusty at first orbicular, and 

 spreading- concentrically ; at last irregular in form, 

 following the sinuosities of any body to which it 

 may be attached. A small portion, viewed verti- 

 cally under the microscope, shows minute cells lying 

 in a clear jelly. When in fruit the surface is pitted 

 with disk-like depressions, pierced by a hole which 

 communicates with a chamber in which the spores 

 lie. Colour variable; now a bright, now a dull 

 red." Harv. Man. 2nd Ed. p. 110. 



