122 
C. quadratum, var. minus. Grun.—C. binoculatum, Breb.—C. 
Meneghinii, Breb.—C. subcrenatum, Naeg.—C. crenatum, 
Ralfs.— C. retusum, Perty.—C. ornatum, Ralfs.—C. celatum, 
Ralfs.—C. Broomei, Thwaites.— C. protractum, Naeg.— C. orbi- 
calatum, 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, semi- 
cells 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 ellip- 
tical, with a deep constriction in the middle. Length of frond 
-0058”—0063." Width .0036”—004.” 
C. pectinoides, vp. sp.—Frond suborbicular, somewhat longer 
than broad, constriction linear. Segments semiorbicular, undulate 
on the margins with twenty or more crenulations, roughened with 
geminate rows of pearly granules symetrically arranged in radia- 
ting lines. On green fronds the united twinned granules appear 
oblong and the crenulations somewhat dentate. Each segment fur- 
nished at base with a rounded protuberance most distinctly evi- 
denced by side view. The resemblance to forms of many seaside 
shells suggested the name. Frond .0025” long, and .0018” broad. 
14. Euastrum, Ehrb.—E. verrucosum, Ehrb,—£. pectinatum, Breb. 
—E. oblongum, Ralfs.—E. ampullaceum, Ralfs.—E. didelta, 
Ralfs.—E. elegans, Ktz.—E. binale, Ralfs.—E. ornatum, Wood. 
--—KE. circulare, Hassel.—Z. rostratum, Ralfs. 
15. Micrasterias, Ag:—M. oscitans, var. pinnatifida, Ktz. var. in- 
Jlata, new.—M. Americana, var. recta, new.—M. Crux-Meliten- 
sis, Ralfs—M. truncata, Breb.—M. furcata, Ag.—M.. Jenneri, 
Ralfs.—M. foliacea, Bailey.—M. multifida, n. sp.—M. denticula- 
ta, Breb.—M. disputata, Wood.—M. muricata, Ralfs. 
Three -forms are considered new. M. oscitans, var. inflata, 
differs from the typical forms in having the lateral lobes not 
“narrow and conical” but broad, with sides nearly parallel and 
often inflated or widened at the ends. M. Americana, var. recta 
differs from the normal form in having the terminal lobe, not “ con- 
cave and bipartite at the angles,” but straight and entire, with two 
conical tubercles on the margin towards the lateral ends. 
M. multifida, vn. sp. Frond punctate, five lobed: basal lobe 
bifid, and middle lobe trifid, and each section again bifid, and 
by a shorter sinus bifurcate at apices; or, segments may be called 
eleven lobed ; the lateral lobes deeply bisected, sinus more or less 
rounded at base, sections forked. Terminal lobe narrow, not 
exerted, sinus wide, angles bifurcate. Rarely with nine lobes. 
005” wide. 005’”—006” long. 
16. Staurastrum, Meyen.—St. muticum, Breb.—St. orbiculare, 
Ralfs.— St, brevispina, Breb.—St. Dickiei, Ralfs—St. dejec- 
tum, Breb.—St. Avicula, Breb.—St. brachiatum, Ralfs.—Sé. 
bifidum, Breb.—St. Margaritaceum, Menegh.—St. dilatatum, 
