l;3-2 FRESH -WATER A L G .E OF THE UNITED STATES. 



C. iindiilatiiin, Corda. 



C. submediucrt', obloiigum, diamutro subdiipli) lungius, utroque polo late rotundatum, aiiibitu 

 leviter sinuato-undulaliim, prol'uiidi! constrictuin, siiiu liueari extrorsum paulluni ampliato; 

 seniicellulis scmiorbicularibus, et dorse et latcribus late rotundatis, margine undulato-creuatis, 

 crenis 9, sublatis ; cytiodermate liBvi ; zygosporis spliaericis spinis elougatis, apice bi- tri-fidis 

 obsitis. (R.) Species inilii ignota. 



Long. 0.0024". Lat. 0.0017". (R.) 



^yn. — C. undulatum, Corda. Rabenhorst, Flora Europ. Algarum, Sect. III. p. 165. 



Hab. — South Carolina ; Rhode Island ; Bailey. 



Frond rather larger than that of C. crenatum, slightly longer than broad, constrictions linear; 

 segments semiorbicular, ends and sides broadly rounded, crenate or minutely undulate at the 

 margin ; e. v. elliptic. Sporangium orbicular, spinous ; spines elongate, slender, swollen at 

 the base and divided at the apex. (A.) 



b. Semicellidse medio-venlricoso injlalx. 



b. Semicells mcdianbj venlr'icose. 



* Cyliodermale leevi. 



* Gyiiuderm smooth. 



C Sllblobntiiiii, (Breb.) Archer. 



C parvum, oblongo subquadratum, diaraetro subduplo longius, sinu angusto linoari; seniicel- 

 lulis subquadratis, e basi dilatata ad verticem sensim angustatis, angulis et iuferioribus et 

 superioribus rotundatis, dorso late truncatis lateribusque leviter sinuatis ; cytiodermate 

 Isevissimo. (R.) 



Long. 0.00119"— 0.00196". Lat. max. 0.0015"— 0.00157". (R.) 



Syn. — G. sublobatum, (Brebisson) Archer. Pritchard's Infusoria, p. 731. 



Hab. — Georgia; Florida; Rhode Island ; Bailey. 



Frond scarcely twice as long as broad, oblong ; constriction linear, segments subquadrate, 

 somewhat wider at the base, lateral and end margins slightly concave, smooth and trans- 

 verse vein cruciform. (A.) 



* * Cytiodermale granulate. 



* * Gylioderm granulate. 



C. ornatiiin, Ralfs. 



C. parvum, plerumque tam longum quam latum ; semicellulis reniformibus, diametro duple 

 longioribus, angulis inferioribus una cum lateribus rotundatis; dorso sub-producto late trun- 

 catis; cytiodermate granulato-verruculoso ; zygosporis longc spinosis, spinis elongatis apice 

 furcatis. (R.) Species inihi ignola. 



Long. 0.0016"— 0.0015". Lat. 0.0010". (R.) 



Sijn. — C. ornatum, Ralps, British Desmidiea3, p. 104. 



Hab.— Rhoda Island; (S. T. Olney) Thwaites. 



Frond in f. v. about as long as broad, constriction deep, linear; segments semiorbicular or 

 subreniform, with a central truncate projection at the ends produced by the continuation of a 

 central inflation, rough towards the margin and on the inflation with pearly granules; e. v. 

 with a rounded lobe on each side. Sporangium orbicular, spinous; spines elongated, dilated 

 at the base and slightly divided at the e.xtremity, 5J3". (Archer.) 



C. coinnii!$!i«iiraIe, (Breb.) 



C. minutum, fere dimidio latins qnani longum, profundi.ssime constrictum, sinu amplo basi ex- 

 cavato; seniicollnlis angusto renifcn-milius, diametro jiaene trijilo longioribu.s, leviter inciuvis, 



