187 
duobus tribusve ultimis amplis sinu profundo. Long. .0026”~.003”" ; 
lat. .0024"-.003”. Sphagnumswamps. In size and general form this 
Desmid is near C. Botrytis and C. Ungerianum, but differs conspicu- 
ously in the irregular size of the crenulations, the unusual promi- 
nence of those next the outer angles, and the plane truncate apices. 
43. Arthrodesmus, Ehrb.—A. octocornus, Ehrb. Ponds. 
ZYGNEMACEAE, Etc. 
44. Spirogyra, Link.—Sp. tenuissima, Ktz—Sp. communis, 
Ktz. Ponds.—Sp. Grevilliana, Ktz. Fresh water pools. : 
45. Rhynchonema, Ktz.—Rh. vesicatum, Hassel. Small pools. 
46. Lygnema, Ag.—Z. Stellinum, Ag.—Z. Vaucheria, Ag. Quiet 
waters. 
47. Mesocarpus, Hassel.—M. scalaris, Hass. Dr. Wood quotes 
this genus, but illustrates a young fruiting specimen of Pleurocarpus; 
hence it may be questioned whether he saw a genuine specimen.— 
M. nummuloides, Hass.—M. angustus, Hass, Both frequent in pools, 
wet rocks, etc. 
48. Vaucheria, DC.—V. uncinata, Ktz.—V. Dillwinii, Ag. In 
addition, I found for the first time the following, quoted by Dr. 
Wood: V. geminata, V. aversa and V. caespitosa.—V. reptans, on last 
list, should be repens. 
49. Prasiola, Ag.—P. Mexicana, Liebm. This interesting plant 
was collected by Mr. Brandegee, attached to stones in rapid waters, 
in the high mountain regions of Colorado. 
so. Gloeotila, Ktz.—G. mucosa, Ktz. Small pools. 
51. Microspora, Thuret.—M. floccosa. Streamlets of spring 
water, Penn. and Col.—M. fugacissima, Roth. Rain water pool in 
woodlands. —M. vulgaris, Rabenh. Frequent in trenches.— M- 
laevis, Rabenh. Spring waters, here and in Florida.—M. amoena, 
Ktz. Ponds.—M. punctalis, Rabenh. Meadow pools, etc. 
52. Conferva, Link.—C. affinis, Ktz. Ponds.—C. utriculosa, 
Ktz. ' Ponds.—C. rhypophila, Ktz. Slow river waters, Harrisburgh. 
53. Cladophora, Ktz.—Cl. flavescens, Ag. I find a variety in 
large ponds which agrees well with this species; however, not 
“ submarine.’—Cl. crispata, Grun., va”, vitrea, Ktz.- Pools.—Cl. hor- 
rida, Ktz., a var. of Cl. fracta, Dillw. Yellowstone Springs, Col. 
Collected by T. C. Porter.—Cl. insignis, Ag. Florida. (J.D. Smith.) 
—Cl. rigidula, Ktz. Cold springs.—Cl. aegagropila, Linn. Sluggish 
waters, 
Cl. Vaucherioides,n. sp. Cl sordide viridis ; libere natans, aggre- 
gata, nubeculas formans, subrigida; ramis subelongatis, secundis, 
tenuibus; filamentis .004’’-.005”, articulis longissimis, 12-20-plo 
longioribus; cytioplasmate granulato, effuso, parietali; cytio- 
dermate laevo, tenui, homogeneo, Vaucheriae simili; septis trans- 
versis filamentorum et ramulorum tenuissimis, indistinctis, saepe 
difficile visibilibus ; geniculis non constrictis; ramulorum insertione 
non apicali, Small ponds. The thin cytioderm, the very thin — 
division walls, and the long cells characterize this plant as a very 
distinct species. : ; 
54. Oedogonium, Link.—Oed. rostellatum, Pringsh.—Oed. vesi- 
