K X I' I. A N A T 1 <> N O F T II F PLATES. 257 



PLATE X. 



Fig. 1 a. A frond of ,s'/rox//./in j'uldnalus, Brib., var. paw/*, from a specimen collected by 

 Ih. .1. (I. Hunt, near rhiluili-l|ihia. The (T round color of this figure is too yellow. 

 Fig. 16. A fragment of the same, magnified 4CO diameters. 



Fijr. '2. A row of colls of Pleurococcun gerialun, Wood, magnified 460 diameters. 



Fig. So. A portion of the old external part of a mass of Palmclla Jessenii, Wood, magnified 750 

 diameters. 



Fig. .'! l>. \ fragment from the interior of such a mass of the same amplification. 



Fig. 3 c. A portion of the soft jelly of a young actively growing muss, magnified 750 diameters. 



Fig. 4. A frond of Dictyosphserium pulchellum, Wood, magnified 460 diameters. I at first 

 referred this plant to the genus BOTBYOCOOCUS, and distributed some specimens under that generic title, 

 and so marked my original drawing. 



Fig. ft. A slice of a youngish frond of Palmella dura, Wood, magnified 460 diameters. 

 Fig. . r i /-. A fragment from an old frond, showing the spores in various stages of growth. The 

 color of the large spores is not nearly dark enough, it should be much more brownish. 



PLATE XI. 



Fig. 1. Different forms of Scenesdesmus polymorphic, Wood, magnified 450 diameters. 

 Fig. 2. Scenedftmtu quadricauda, Breb., magnified 750 diameters. 

 Fig. 3. Scenedesmus rotundalus, Wood, magnified 750 diameters. 



Fiir. 4. Ordinary vegetative cells of Falmogitra clepttydra, Wood, in different stages or con- 

 ditions of life-history, magnified 750 diameters. Those cells which have the cndochronic much 

 broken up are believed to be preparing for conjugation. 



Fig. 4 a. A pair of cells uniting in conjugation. 



Fiir. 4 6. Cells which have united so that the young spore is very apparent with the empty semi- 

 cells of the parents attached to it 



Fiji. 4 c. A more advanced spore and empty semi-cells. 



Figs. 4 d and 4 e. Matured or nearly matured spores, as seen with different focussing; in Ihe 

 first the upper surface of the spore is especially brought out. All these figures, except 4 b, are 

 magnified 750 diameters. 



Figs. 5 and 5 a. Different forms of Closlerium acerosum (Scbr), magnified 250 diameters. 

 Fig. 5 6. Empty conjugating cells with nearly matured spore. 



Fig. 6. Outline of Closlerium areolalum, Wood, magnified 160 diameters. 

 Fig. 6 a. End of a dead, empty frond, enlarged 1375 diameters. 



Fig. 7. Outline of Closterium Venus, Ktz., magnified 450 diameters. 

 (These last three species are incorrectly labelled on the plate, Cosmarium.) 



PLATE XII. 



Fig. 1. Closlerium lincatum, Ehrb. (Incorrectly labelled on the plate Cosmarium.) Magni- 

 fied ICO diameters. 



Fig. 2. Closlerium Ehrenberyii, Menegh., magnified 160 diameters. 

 Fig. 3. Closte.rium rostratum, Ehrb., magnified 260 diameters. 

 Fig. 4. Closterium Dianse, Ehrb., magnified 260 diameters. 



Fijr. ft. riimfrriiim jwrrulum, Nieg., magnified 450 diameters. 

 33 October. 1872. 



