285 [Cras 2Larro) 
causing the filaments to appear crenate or corrugate. The 
other variety “ bruneum” is dark brown. The filaments are . 
covered with what appear to be subspherical resinous cells. 
This is probably an older form of the corrugatum variety. The 
term “cortex” is significant and should be retained ; then 
Ravenelit, corrugatum, and possibly druneum would be varieties. 
The other forms of this genus have their parts in accord with 
accepted descriptions, but Iam by no means satisfied that all 
are distinct species. I accept the dicta of the fathers until a 
fuller light dawns. 
Calothrix, Ag.—C. mirabilis. Ag. Falls of Deep Creek, Md. 
Coll. J. D. Smith. 
-Tolypothrix, Ktz.— 7. Ravenelit, n. sp. T. in strato minus expanso, 
aureo-fusca, trichomatibus pseudoramulisque elongatis ; inter- 
nis flavo-rubescentibus saepe interruptis, distincte articulatis, 
articulis gracillime granulosis, diametro subaequalibus vel duplo 
brevioribus; vaginis subarctis, luteo-fuscescentibus; cellulis 
perdurantibus basilaribus et interjectis, plerumque singulis, 
oblongis, luteolis. Diam, cum. vaginis .0006”—ooo8”, rarius 
-,oo1”. Hab. in rupibus aquae dulci expositis. 
’ This plant was found on sand stone rock, Gainesville, Fla., 
by Mr. Ravenel. It is nearest to T. distorta, but differs in 
size, in articulation, in the character of the heterocysts, and 
in habitat. : 
Hapalosiphon, Naeg.—H, Braunii, Naeg. Not infrequent in fresh 
and salt water, in limited quantity, from Pennsylvania to 
Florida.—H. fuscescens, Ktz. Dr. Rabenhorst remarks on this 
species, “ ab antecedente vix diversus.” 
The plant I place here is more distinct; the articulations 
of the rhizoma are usually subequal and. moniliform, and those 
of the branches one to two diameters in length. Frequent in 
pond at Pleasant Mills, N. J. Young forms of this genus may 
be readily reconciled with the characters of the genera AZast1- 
gocladus, Cohn, and Noastochopsis, Wood. 
Sirosiphon, Ktz.—S. ocellatus, Ktz. not infrequent in wet and 
swampy places. 
Much might -be said of the propagation of plants. of this 
genus. ‘Space would not admit of it here. 
CHLOROPHYLLOPHYCEAE. 
Scenedesmus, Meyen—S. antennatus, Breb. Coli. J. D. Smith, 
Florida, 
Characium, A. Braun.—C. strictum, A. Br. Parasitic on filamen- 
tous plants. 
DESMIDIACEAE, 
Tetmemoras, Ralfe.—T. granulatus, Breb.—T. Brebissonii, Menegh. 
Florida, J. D. Smith. : 
-Sphaerozosma, Corda.—S. serratum, Bailey. Frequent in S. Caro- 
lina and Florida. Coll. H. W. Ravenel and J. D. Smith.—S. 
-, filiformis, Ehrb, Coll. H. W. Ravenel, Georgia. 
