FRESH-WATER ALGiE OP THE UNITED STATES. 213 



able to identify them. One of the forms grows in this immediate locality, and is very 

 probably G. scutata, Breb. The other was collected in Northern Michigan. It is 

 characterized by its frond never being disciform, although composed of a single 

 plane of cells parenchematously united. 



Class RHODOPHYCEJE. 



Algae multicellulares, vegetatione terminalis non limitata praeditse 

 plerumque trioicae. 



Thallus e cellularum seriebus vel stratis singulis vel pluribus compo- 

 situs, aut nudus aut e cellularum strato corticatus, forma quam maxime 

 varius; membratiaceus (Porphyridium), crustaceus (Hildenbrandtia), 

 filamentosus et verticillatim ramosus (Batrachospermum, Thorea), fascii- 

 formis (Bangia), foliaceus, etc. 



Cytioplasma plerumque rhodophyllo (Oohn), rarius phycho-chromate 

 coloratum, granula amyloidea vel amylacea et s£epe guttulas oleosas 

 includens. 



Propagationis organa triplicis indolis, saepissime in plantas distinctas 

 disposita. 



1. Organa mascula vel antherida e fasciculis cellurarum plerumque mo- 

 niliformibus ramosis, denique in spermatozoidea vel spermatia foecun- 

 dantia [Sporidia I. Ag.) oblonga vel ovalia, achrod, immobilia dissolutis 

 formata. 



2. Organa feminea vel cystocarpia Ktz, e soris nonnunquam monilifor- 

 mibus formata, qui e placenta saepissime corticali evolvuntur, nudi vel 

 cuticula mucilaginosa vel involucre inclusi, denique sporas {polysporas) 

 numerosas immobiles mox germinantes emittunt. Foecundatur cysto- 

 carpium statu primordiali ope organi piliformis {^richogyne Thuret et 

 Bornet) quorum spermatia copulantur. 



3. Tetrasporangia e cellula corticali unica valde intumescente formata, 

 divisione utriculi primordialis cruciata quadrilocularia ; in quoque loculo 

 {cellulis secundariis, sororiis) spora unica {tdraspora) se format, quae sine 

 fcecundatione germinat. (E.) 



Multicellular algge, mostly triaecious, furnished with unlimited not ter- 

 minal vegetation. 



Thallus composed of cells in rows or in a simple or multiple stratum, 

 either bare or provided with cortical strata of cells, exceedingly various 

 in form; membranaceous (Pophyridium), crustaceous (Hildenbrandtia), 

 filamentous and verticillately branched (Batrachospermum, Thorea), 

 fasciate (Bangia), foliaceous, &c. 



Cytioplasm mostly rhodophyllous, rarely phycochromatously colored, 

 including amyloid granules or starch and frequently oil drops. 



Propagation by means of three immotile organs, generally placed 

 upon distinct plants. 



1. Antheridia composed of mostly moniliformly branched fascicles of 



