XIV. A.LGM. 



907 



Delesseria rutcifolia. Branch bearing a coccidium. 



Plocamium vulyare. 

 Portion of sterile branch. 



Delesseria rutcifolia. 

 Coccidium cut lengthwise (mag.). 



Delesseria ruscifolia. 

 Tetraspore (mag.). 



Plocamium. 



Portion of branch, bearing a 

 favella. 



Plocamium. 

 Stichidium contain- 

 ing quaternary 

 spores (mag.). 



Plocamium, 



Favella cut, 



containing globular 



spores (mag.). 



Delesseria rusafMa. 



Portion of frond bearing 



tetraspores along the 



median nerve (mag.). 



Oorvtllina officinalii. 



Fructiferous branch 



(mag.). 



Corallina cupi-essina, 

 Section of a branch 



terminated by a 

 oeramidiam (mag.). 



several tubes composing a simple filamentous stem (Polywphonia, &c.), or of mem- 

 branous irregular fronds (Porphyra), or apparently foliaceous (Delesseria) or cartila- 

 ginous (Iridea), with or without nerves, entire, or latticed (Hemitrema, Thuretta), or 

 umbellate (Constantinia), or lomentaceous (Catenella), or Jungermannoid (Leveillea, 

 Polyzonia), sometimes encrusted with lime and fragile (Corallina, &c.). REPEO- 

 DUCTIVE ORGANS of two kinds, monoecious or dioecious. Sporangia superficial, or sunk 

 in the frond and contained in conceptacles of various forms. Spores rounded or 

 oblong, solitary or quaternary. Antheridia of various form, or making a part of the 

 tissue of the frond, composed of colourless cells, each containing an antherozoid with 

 no vibrating hairs or power of motion. The antherozoids fertilize the sporangium 

 by means of a special tube (trichogyne). 



Cruorm. 



Porphyra. 

 Bangia. 



Wrangelia. 



Nemalium. Bornetia. 



Batrachospermum. Naccaria. 

 Liao-ora. Spermothamnion. 



Helminthora. Ceramium. 



Microcladia. 



PKINCIPAL GENERA. 



Thamnidiurn. Dumontia. 



Chondrus. 



Gigartina. 



Callymenia. 



Gymnogongrus. 



Phyllophora. 



Peyssonnelia. 

 Rhododermis. 



