114 FRESH-WATER ALGiB OP THE UNITED STATES. 



" Frond smaller than C. Ehrenbergli, stout, five or six times as long as broad, Innately curved, 

 extremities tapering, upper margin convex, lower concave, with a central inflation, ends 

 rounded ; large granules, conspicuous, in a single longitudinal series ; e. f. colorless, without 

 striae, suture not evident. L. ^^" — ^V'- ^- jW — jW Archer." Pritchard's Infusoria, 

 p. 748. 



C. Leibleinii, Ktz. 



C. priore minus, semilunare, magis incurvum, ventre inflate, ad utrumque polum largius attenu- 

 atum, apicibus achrois acutis; vesiculis chlorophyll, in quoque crure 5-6, in serie simplici 

 axillari dispositis; locello magno, apices versus sito, corpuscula numerosa includente. (R.) 



IHam.—^ly. 



Syn. — G. LeiUeinii, Kutzing. Rabenhorst, Flora Europ. Algarum, Sect. III. p. 132. 



Hah. — Georgia ; Rhode Island ; Bailey. Pennsylvania ; Wood. 



" Frond somewhat stout, distance between the extremities six or eight times the breadth, 

 crescent-shaped, much curved, rapidly attenuated, upper margin very convex, lower very con- 

 cave, often with a slight central inflation ; ends subacute ; large granules, in a single series ; 

 fillets few or indistinct ; e. f. somewhat straw-colored, without strise; suture evident. Spo- 

 rangium orbicular." Archer. 



Remarh. — Fig. 6, pi. 12, represents this plant, magnified 260 diameters. 



4. Cellulae maxime curvalae, ventre non fumidee. 

 4. Cells most curved, the belly not tumid. 



C. Dianae, Ehrb. 



C. anguste fusiforme, semilunare, utroque polo valde attenuatum, apicibus subacutis ; cytioder. 

 mate achroo (vel dilutissime umbrino), striis subtilissimis medio interruptis prsedito, in media 

 parte striis transversalibus 3-5; vesiculis in quoque crure 6-7, in serie unica axili dispositis- 

 laminis chlorophyllaceis pluribus, saepe flexuosis; locello indistincto, corpusculis pluribus 

 vivide mobilibus. (R.) 



Diam.—La.t. t/tj/ =.00053". Long, .yf f^' = .00082". 



Syn. — C. Dianse, Ehrenberg. Rabenhorst, Flora Europ. Algarum, Sect. III. p. 133. 



Hob. — Georgia.; Florida ; Rhode Island ; Bailey. Pennsylvania ; Wood. 



Frond crescent-shaped, six or eight times as long as broad, much curved, rapidly attenuated • 

 upper margin very convex, lower very concave without a central inflation ; ends subacute 

 with a very slight emargination at the upper outer extremity ; large granules in a single 

 series; empty frond, somewhat straw-colored, or faintly reddish, without stris, suture evident 

 (A.) 



Rema/rhs.—M.x. Archer marks G. Vetms, Ktz., as a doubtful synonym of this 

 species ; not having Prof. Kiitzing's work at hand, I do not know whether G. 

 Venus, Ktz. is reaUy the following species or not. The two forms here known as G 

 Diance, Ehrb. and C. Venus, Ktz. are, however, I think sufficiently distinguished! 



Fig. 4, pi. 12, represents this species of desmid. 



C. Venus, Kiz. 



C. parvum, plus minus gracile, semicireulare, octies-dnodecies longius quam latum, in apices 

 subacutos sequahter sensimque attenuatum ; cytiodermate tenui, laBve ; laminis chlorophylla- 

 ceis obhteratis; vesiculis in quoque crure 3-4; locello distincto corpusculis 4-6 replete (R.) 

 Diam.—.000i". 



