116 FRESH-WATER ALG^E OF THE UNITED STATES. 



Diam. 0.0008". (0.0009"-0.0016." R.) 



Syn. C. rostratum, EHRENBERG. RABENHORST, Flora Europ. Algarum, Sect. III. p. 135. 



Hob __ In fossis, prope Philadelphia; Wood. 



Body lanceolate-fusiform, at each end greatly and for a long distance attenuated, slightly curved, 

 striate ; crura setaceous and scarcely as long as the body and sometimes much shorter; cytio- 

 derm light or luteolous, densely striate, vesicles uniseriate, 5-6 in each eras ; vacuoles oblong, 

 often indistinct, containing from 12-15 actively moving granules. 



Remark. Fig. 3, pi. 12, is a drawing of this species, magnified 260 diameters. 

 . setaceum, EHRB. 



C. corpore anguste lanceolate, recto vel subrecto, distincte striato, utrinque in rostrum setaceum, 

 levissime incurvum, obtusum, longissirae porrecto; singulo rostro corpore 3-4 plo longiore; 

 et vesicnlis et locello indistinctis. (R.) 



Diam. Max. (plerumque) 0.0004" 0.00044." (R.) 



Syn. C. setaceum, EHRENBERG, Flora Europ. Algarum, Sect. III. p. 136. 



Hob. Stonington. (Lewis) Pennsylvania ; Wood. Georgia ; Florida ; Providence, Rhode 

 Island ; Bailey. 



Frond very slender, from twenty to twenty-five times as long as broad, narrow-lanceolate; 

 upper and lower margins nearly equally and but slightly convex ; each extremity tapering- 

 into a very long and slender setaceous colorless beak, longer than the body, ultimately curved 

 downwards, ends obtuse; e. f. colorless, strise close, faint, central suture solitary. Sporangium 

 cruciform. L. TTS"- B. ^T"- Archer. Pritchard's Infusoria. 



C. Amlil.voiiciiin, EHRB. 



C. filiforme, cylindricum, laeve, utroque fine parum attcnuatum, apice rotundum. (R.) 

 Syn. G. lineatum, EHRB. BATLEY, American Journal of Science and Arts, 1841, p. 303. 



G. Amblyonema, EHRB. Verbreit. p. 123. RABENHORST, Flora Europ. Algarum, Sect. 

 III. p. 138. 



Hob. West Point, New York ; Providence, Rhode Island, Bailey. 



Filiform, cylindrical, smooth, gradually attenuated at each end ; the apex rounded. 



Remarks. I have never recognized a specimen of this species, nor have I had 

 access to the original description of Ehrenberg. 



Genus TETMEMORUS. 



Cellnlee cylindricae vel fusiformes, rectae, medio distincte constrictse, utroqne polo anguste incisae 

 cytioderma sat firmum, plerumque granulatum vel punctatum. 



Cells cylindrical or fusiform, straight, distinctly constricted in the middle, narrowly incised at 

 each end. Cytioderm firm, mostly punctate or granulate. 



T. Brebissonii, (MENGH.) RALFS. 



T. diametro 4-6 plo longior ; a fronte cylindricus, utroqne polo non attenuates sed rotundato- 

 truncatus ; a latere fusiformis et a medio in apices rotundatos sensim attenuatus ; cytiodermate 

 striato-punctato. 



Diam. 7 ^ ff " = .0016". 



Syn. T. Brebissonii, MENGHEINI, RABENHORST, Flora Europ. Algarum, Sect. III. p. 139. 



