78 FRESH-WATER A L G yE OF THE UNITED STATES. 



ORDER CoCCOphycCSC. 



Alga: unicellulares. Cellulae ant singulse (plerumque perfecte scgregatae) aut plures in familias 

 consociatas, tegumentis involutae vel nudse, aut ramificatione aut vegetatioue terminal! destitute;. 

 Propagatio fit aut cellularum divisione aut zoogonidiis. 



TJnicellular algse. Cells either single (mostly entirely segregate), or mostly consociated in fami- 

 lies, walled or clothed with teguments, destitute of branches or terminal vegetation. Propagation 

 by means of zoospores, or by the division of the cells. 



FAMILY PALMELLACE.E. 



Algae unicellulares sensu latiori. Cellulse aut singulse aut numerosae, familias constituentes, in 

 muco matricali plus minus firmo, stratum gelatinosum amorphum, saepius figuratum, tubulosum 

 (Hormospora) varie divisum et perforatum (Tetraspora), quasi ramificatum (Hydrurus) formante 

 nidulantes, vel nullo (Rhaphidium, Dactylococcus). Cytioderma plerumque tenue, saepius tegumento 

 gelatinoso aut homogeneo aut lamelloso praeditum. Cytioplasma homogeneum, aetate provecta ple- 

 rnmque distincte granulosum, viride, aut rubescens aut fuscescens, vesicula chlorophyllosa semper 

 instructnm (excepto Rhaphidio). 



Multiplicatio fit cellularum divisione vegetativa, propagatio gonidiis ex ultima ccllularum gene- 

 ratione transitoria cytioplasmatis divisione varia ortis. Gonidia tegumentis liberata, polo autico ciliis 

 vulgo binis plerumque instructa et alacriter circumvagantia. (R.) 



Algae unicellular in a broad sense. Cells either single or numerous, constituting families, imbedded 

 in a jelly to form a gelatinous stratum which is amorphous or shaped, as tubular (Hormospora), 

 variously divided and perforate (Tetraspora), falsely branched (Hydrurus), or sometimes is wanting 

 (Rhaphidium, Dactylococcus). Cytioderm mostly thin, often furnished with a gelatinous or homo- 

 geneous or lamellate tegument. Cytioplasm homogeneous, mostly at maturity distinctly granular, 

 green-reddish or fuscous, always furnished with a chlorophyllous vesicle (except Rhaphidium). 



Multiplication taking place by a vegetative division of the cells, propagation by transitory gonidia 

 arising by various divisions of the protoplasm from the last vegetative generation. Gonidia with- 

 out integument, mostly furnished with two cilia at the anterior end, and moving about actively. 



Genus PLEUEOCOCCUS, MENGH. (RABENH.) 



Cellulae globosse vel e mutua pressionc angulosae, plerumque nucleo instructae, turn singialae turn 

 in familias consociatae. Cytioderma firnium, ssepe crassum, laeve, hyalinum ; cytioplasma homoge- 

 neum viride vel oleosnm rubrum. Multiplicatio cellularum vegetativarum divisione in directiouem 

 ad omnes dimensiones altcrnantem. Propagatio fit gonidiis intra sporangia ortis. 



Cells globose or angular from mutual pressure, mostly furnished with a nucleus, sometimes single, 

 sometimes aggregated into families. Cytioderm firm, often thick, smooth, hyaline ; cytioplasm 

 homogeneous-green or oleaginous-red. Multiplication occurring by a vegetative division of the 

 cells alternately in three directions. Propagation by means of gonidia, formed within sporangia. 



P. serial us, WOOD, (sp. nov.) 



P. corticolus, strata pulverula, rubido-brunnea, nonnihil Crustacea formans ; cellulis enormiter 

 subglobosis, vel ovalibus, laete aurantiacis, interdum viride tinctis, hand distincte nucleatis, in 

 seriebus singulis rectis vel curvatis conjunctis ; tegumentis crassis, baud lamellosis, coloris 

 expertibus. 



Diam._ 7E V' T S V = .00053" .0012". 

 Eab. In palude. New Jersey. (Austin.) 



Growing on bark, forming a reddish-brown, somewhat crustaceous powdery mass; cells irregu- 

 larly subglobose, or oval, bright orange, sometimes tinged with green, not evidently nucleated, 

 conjoined in single straight or curved series; tegument thick, lamellate, or not so, colorless. 



