138 FRESH-WATER ALGJE3 OP THE UNITED STATES. 



Fig. 12, pi. 21, represents the front view of an empty half frond of this species, 

 magnified 450 diameters ; fig. 12 a, the side view of an empty frond. 



E. affine, Ralfs. 



E. E. humerosum afflne, paulo minus ; semicellulse quinquelobse ; lobi basales quales in B. hume- 

 rosum sed tumores quatuor in seriem transversam simplicem dispositi, lobi intermedii valde 

 abbreviati eorumque basi tumoribus duobus instructi, lobus polaris magis porrectus et in 

 apice minus dilatatus; cytioderma subtilissime punctatum sublseve. (R.) 



Long. 0.0038"— 0.0041". (R.) 



Syn. — H. affine, Ralfs, British Desmidese, p. 82. 



Eab. — South Carolina ; Georgia ; Bailey. 



Frond about twice as long as broad ; segments 3-lobed ; basal lobes slightly emarginate, 

 having intermediate between them and the end lobe on each side a tubercle representing 

 middle lobes, the upper margin of which is horizontal ; end lobe exserted, dilated, its notch 

 linear. 



Empty frond ; f v. minutely punctate ; the segments with four basal inflations, two above and 

 two on end lobe ; tr. v. elliptic, with four inflations on each side and one at each end ; e. v. 

 end lobe emarginate at opposite ; e. v. end lobe emarginate at opposite external margins, 

 producing four shallow lobulets. (A.) 



E.Didelta, (Turpin) Ralfs. 



E. robustum, diametro duplo longius etiam supra, in sectione transversa ellipticum, ambitu un- 

 dulato-crenatum, in utroque latere crenis quaternis ; semicellulis pyramidal ibus, quinquelobis, 

 tumoribus 9 in series tres alternantibus ordinatis, lobis inferioribus oblique truncato-rotundatis 

 nonnunquam leniter retusis, intermediis subadscendentibus, rotundatis, lodo polari minus 

 dilatato, bifido, segmentis rotundato-truncatis, conniventibus, in apice tumidis ; cytiodermate 

 distincte punctato, punctis modo irregulariter sparsis modo in seriebus rectis collocatis. (R.) 



Long. 0.0055" Lat. 0.00279". 



Syn-r-E. Didelta, (Ttjrpin) Ralfs, British Desmidese, p. 84. 



Hab. — South Carolina ; Georgia ; Rhode Island ; Bailey. Pennsylvania ; Wood. 



Frond rather more than twice as long as broad; segments pyramidal, inflated at the base and 



again at the middle, end scarcely dilated, rounded, its notch linear. 

 Empty frond punctate ; f. v. segments with several inflations in lines and two at the end ; tr. v. 



elliptic with four inflations at each side and one at each end ; e. v. end lobe entire at margin. 



Sporangium orbicular, with subulate spines. (A.) 



Bemarh. — Fig. 13, pi, 21, represents this species. 



E. ampnllaceum, Ralfs. 



E. diametro duplo longius ; semicellulis trilobis, ad basin tumidis. e basi latissima subito in lobi 

 polaris collum attenuatis, lobis basalibus maximis integris, loco loborum intermediorum pro- 

 cessu deutiformi, lobo polari cuneato, in apice bifido, segmentis late truncato-rotundatis; 

 cytiodermate subtiliter punctate. (R.) 



Long. 0.0035"— 0.0038". Lat. max. .0026"; lat. in colli (lobi polar.) 0.00085". (R.) 

 Syn. — E. ampuUaceum, Ralfs, British Desmideae, p. 83. 

 Sab. — South Carolina; Florida; Bailey. 



Frond rather more than one-half longer than broad ; segments obscurely 3-lobed, short, with 

 broad inflated base ; basal lobes not emarginate, having on each upper side a small inter- 

 mediate tubercle between each and the end lobe ; end lobe exserted and dilated, its notch 



