132 FRESH-WATER A L G .E OF THE UNITED STATES. 



C. undulatuin, CORDA. 



C. submediocre, oblongum, diametro subduplo longius, utroque polo late rotundatum, ambitu 

 leviter sinuato-undulatum, profunde constrictum, sinu linear! extrorsum paullum ampliato ; 

 semicellulis semiorbicularibus, et dorso et lateribus late rotundatis, margine undulato-crenatis, 

 crenis 9, sublatis ; cytiodermate leevi ; zygosporis sphsericis spinis elongatis, apice bi-tri-fldis 

 obsitis. (R.) Species mihi ignota. 



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



Syn. C. undulatum, CORDA. RABENHORST, Flora Europ. Algaram, Sect. III. p. 165. 



Hob. 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. Semicellulee medio-ventricoso inflatse. 



b. Semicells medianly ventricose. 



* Cytiodermate Ixwi. 



* Cytioderm smooth. 



C. sublobatum, (BREB.) ARCHER. 



C. parvum, oblongo subquadratum, diametro subdaplo longius, sinu angusto linear! ; semicel- 

 lulis subquadratis, e basi dilatata ad verticem sensim angustatis, angiilis et inferioribus et 

 superioribus rotundatis, dorso late truncatis lateribusque leviter sinuatis ; cytiodermate 

 Iffivissimo. (R.) 



Long. 0.001t9" 0.00196". Lat. max. 0.0015" 0.00157". (R.) 



Syn. C. sublobatum, (BREBISSON) ARCHER. Pritchard's Infusoria, p. 731. 



Nab. 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 granulato. 



* * Cytioderm granulate. 



C. ornatum, RALFS. 



C. parvum, plerumque tarn longnm quam latum ; semicellulis reniformibus, diametro duplo 

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

 catis; cytiodermate granulato-verruculoso ; zygosporis longe spinosis, spiuis elongatis apicc 

 furcatis. (R.) Species mihi ignota. 



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



Syn. C. ornatum, RALFS, British Desmidiese, p. 104. 



Hob. Rhode Island; (S. T. Olney) Thwaites. 



Frond in f. v. about as long as broad, constriction deep, linear ; segments semiorbicnlar 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 extremity, ^ 3 ". (Archer.) 



. commissiirale, (BREB.) 



C. minutum, fere dimidio latins quam longum, profundissime constrictum, sinu amplo basi ex- 

 cavato ; semicellulis anguste reniformibus, diametro paene triplo longioribus, leviter incurvis, 



