^S. Montagnei.^ This species resembles /S. vulgare/, but is more slender in all its parts, and the receptacles are more elongated. From south of Cape Cod. ^S. bacciferum.^ Particular interest attaches to this species from the fact that it is the one which forms the floating vegetation of the Sargasso Sea. It grows attached on the Florida Keys and in the West Indies. Specimens are sometimes carried by the currents northward, and are found washed ashore. It differs from /S. vulgare/ in the leaves, which are thicker, more attenuated, and sharply toothed, and in having a greater number of air-vessels. A branch of this species brought from the Sargasso Sea had air-vessels so numerous and closely set that it resembled a bunch of small grapes. III RED SEAWEEDS (RHODOPHYCEÆ OR FLORIDEÆ) TABLE SHOWING THE CLASSIFICATION OF THE RED SEAWEEDS DESCRIBED IN THIS CHAPTER Class =ALGÆ= Subclass =Rhodophyceæ or Florideæ= (/Red Seaweeds/) Order =NEMALIONACEÆ= Suborders Genera Species ~HELMINTHOCLADIEÆ~ ^Nemalion^ ^N. multifidum^ ^Liagora^ ~CHÆTANGIEÆ~ ^Scinaia^ ^S. furcellata^ ~GELIDIEÆ~ ^Gelidium^ ^G. corneum^ Order =GIGARTINACEÆ= ^Chondrus^ ^C. crispus^ ^Gigartina^ ^G. mamillosa^ ^G. radula^ ^G. spinosa^ ^G. microphylla^ ^Phyllophora^ ^P. membranifolia^ ^P. Brodiæi^ ^Sternogramme^ ^S. interrupta^ ^Gymnogongrus^ ^G. Norvegicus^ ^Ahnfeldtia^ ^A. plicata^ ^Callophyllis^ ^C. variegata^ ^C. laciniata^ ^Iridæa^ Suborders Genera Species ~RHODOPHYLLIDEÆ~ ^Cystoclonium^ ^C. purpurascens^ ^C. cirrhosa^ ^Euthora^ ^E. cristata^ ^Rhodophyllis^ ^R. veprecula^ ^Rhabdonia^ ^R. tenera^ ^R. Coulteri^ ^Eucheuma^ ^E. isiforme^ Order =RHODYMENIACEÆ= ~SPHÆROCOCCEÆ~ ^Gracilaria^ ^G. multipartita^ ^Hypnea^ ^H. musciformis^