FRESH-WATER ALO^E OF THE UNITED STATES. 135 



Cells small, nuMliptiral, profoundly constricted in the middle, joined by tranalnceDt bands into 

 families; Ki'inirells si-en from tlio front elliptical, and nearly twice aa long aa broad, from the 

 Tvrtcx elliptical, from the side roundish; sinus broad; chlorophyl masses single in each cell; 

 It-nil thin, smooth. 



Remarks. This plant was found by my friend Mr. Quimby growing in a beau- 

 tiful spring above Canulcn, upon whose bottom it formed a gelatinous, trans- 

 lucent, grrrnUh mass. The cells resemble in shape those of C. cucitmu, although 

 much siiKillcr. They arc joined by bands into little families, in which the original 

 parent-cell is iri 'in Tally very distinct, it, or rather the two cells into which it first 

 divides, remaining in the centre of the group. The bands are so hyaline that their 

 edges can alone be distinctly seen, and hence the latter often look as though they 

 were threads there appearing to be two parallel threads, or two threads crossing 

 one another, or a single thread, according as the band is flat, twisted, or on edge. 



It gives me great pleasure to dedicate the species to my friend Mr. Quimby, by 

 whom it was collected. 



Fig. !), pi. 1, represents one of the family groups of this plant. 



Genus EUASTRUM, EHRB. 



Celluhe vel oblonga vel elliptic, medio profunde incisae, symmetrice sinuatae, rel lobatae, tumori- 

 bu> inlliitid circularibus (rare obsoletis) instruct*, utroque polo sinaato-emarginatte vel inciso-bilo- 

 baUe, a vertice elliptic*. 



(Vila either oblong or elliptic, profoundly incised in the middle, symmetrically sinuate or lobed, 

 proviilnl with circular inflated protuberances (which are rarely absent), at each end sinaately emar- 

 ginute or iucisely-bilobate, from the vertex elliptic. 



A. Lobo polares in apict late sinualo-excisi. 



A. Polar lobe with Us apex broadly sinuately excised. 



I!, mult iloha In in, WOOD. 



E. magnum, fere dnplo longias qnam latum, medio profunde constrictnra, et cum sinn modice 

 amplo; a latere medio ventricosum et duplo biumbonatnm, ad verticem dilatatum et emar- 

 ginatum ; semicellulis a fronte trilobatis, lobis sinus amplissimia inter se scjunctia ; lobi basal e 

 distinctc late emarginato, lobo cent rule obtuso, lobo polare late leviter sinnato-emarginato; 

 semieellulis a vertice quinque lobulatis; cytiodermate laevi. 



Diom. Long. rff n " = .00475". Lat. rffa" = .0025". 

 SynE- mtiUilobaium, WOOD, Proc. A. N. S., 1869. 

 Sab In lacu "Ssco;" New Hampshire; (Lewis.) 



E. large, about twice as long as broad, in the centre profoundly constricted, with the sinus 

 moderately large ; from the lateral view somewhat enlarged and doubly biumbonate in the 

 middle ; gemicclls from the front trilobate, the lobes separated by very wide sinuses, the basal 

 lobe broadly emarginate, the central lobe obtuse, the end lobe broadly and shallowly sinuately 

 emarginate; semicells from the vertex 6ve-lobed; cytioderm smooth. 



. The basal lobes of this beautiful desmid are distinctly five lobulate, 

 the lateral lobules being longer and broader than the others, which, instead of 

 bring emarginate, are obtuse. The sinuses, separating lobes and lobules, are very 

 broad, with very obtuse angles. When the desmid is viewed from two-thirds 

 round, so as to show the anterior and posterior lobules especially, it presents an 



