— 15 — 
3) Closterium, Nitzsch. — C.obtusum, Breb. — 
C. angustatum, Ktz. — C. striolatum, Ehrb. — €. lunula, 
Ehrb. C. Ehrb., Menegh. — C. Leibleinii, Ktz. — C. 
Dianae, Ehrb. — C. Venus, Ktz. — C. parvulum, 
Naeg. — C. Jenneri, Ralfs. — C. rostratum, Ehrb. 
sectaceum, Ehrb. — C. moniliferum, Bory. — 
C. lineatum, Ehrb. — C. acerosum, Ehrb. — C. 
turgidum, Ehrb. 
4) Tetmemorus, Ralis. — T. Brebissonii, Menegh. 
—T. kaevis;, Kt 
5) Pleurotaenium, Naeg. — P. Trabecula, Naeg. 
— P. clavatum, Ktz. — P. crenulatum, Ehrb. — 
P. hirsutum, Bailey. — P. nodosum, Bailey. 
6) Spirotaenia, Breb. — S. condensata, Breb. 
7) Sphaerozosma, Corda — S. excavatum, Ralfs. 
8) Hyalotheca, Ehrb. — H. dissiliens, Breb. — H. 
mucosa, Ehrb. 
9) Bambusina, Ktz. — B. Brebissonii, Ktz. 
10) Didymoprium, Ktz. — D. Grevillü, Ktz, 
Il) Desmidium, Ag. — D. Swartzü, Ag. — D. 
Swartzii, var. Ralfsii. — D. aptogonum, Breb. 
12) Aptogonum, Ralfs. — A. Baileyi, Ralfs, finely 
in fruit. 
13) Cosmarium, Corda. — C. margaritiferum, Menegh. 
— (C. Botrytis, Menegh. — C. ovale, Ralfs. — C. te- 
trophthalmum, Ktz. — C. conspersum, Ralfs. 
— G:Portianum, Acker. — C. Ralfs7i;,Breb, 
C.laeve Rab. — C. Cucumis, Corda. — C. pyra- 
midatum, Breb. — C. quadratum, var. minus, 
Grun. — C. binoculatum, Breb. — C. Meneghinii, 
Breb.— C.suberenatum, Naeg. — C. crenatum, 
Ralfs. — C.retusum, Perty. — C. ornatum, Ralts. 
C. caelatum, Ralfs. — C. Broomei, Thwaites. — C. 
protractum, Naeg — C. orbicalatum, 
Ralfs. -— C. Thwaitesii, Ralfs. — C. connatum, Breb. — 
C. connatum, var. minus, new var., differs from 
the typical form mainly in size, being only half as 
large. 
C.dentatum, n. sp. — Frond one-half longer than » 
wide, semicells oval or suborbicular, constriction deep. 
Cytioderm finely and rather closely set with short conical 
pearly granules; the margins of the sides of the segments 
dentate with more distant and larger conical projections, 
ten to twelve on each side. The ends rounded and devoid 
of projecting teeth. End view oval. Side view elliptical, 
