146 FRESH-WATER ALG^ OF THE UNITED STATES. 



• Diam.— 0051"— .0018". (R.) 

 Sjjn. — M. fimhriata, Ralfs, British Desmidiea;, p. 11, et Rabenhokst, Flora Europ. Algarum, 

 Sect. III. p. 193. 



Uab. — South Carolina ; Florida ; Bailey, 



Frond orbicular, smooth; segments 5-lobed, basal lobes twice, middle lobes thrice dichotomous; 

 ultimate subdivisions acutely bidentatc; end lube very slightly esserted, its angles very 

 slightly produced, bidentate, ends eniarginate. In transverse view is seen an inflated pro- 

 tuberance just over the central isthmus, which may possibly exist in other species of Micras- 

 lerias. (A.) 



M. papillirera, Breb. 



M. orbicularis, sujjcrficie hcvis, marginc extremo dentato papillifera; semieellulis quinquelobis ; 

 lobis basalibus et intermediis wquilati.s, bilobatis; lobulis bifidis, laciniis liuearibus bidentatis, 

 dentibus papilliferis ; lobo polari vix promiuulo, in apice siuuato, angulis et margiue deutato- 

 niucronatis. (R.) Upecies mihiignota. 



i?jam.— 0.0045". (R.) 



gyn. — M. papillifera, Brebisson. Ralfs, British Dcsmidica;, p. 12, et Pi4Bi;niiurst, Flora 

 Europ. Algarum, Sect. III. p. 194. 



Hah. — Florida; Rhode Island ; Bailey. 



Frond orbicular, having the principal sinuses bordered by a row of minute granules, otherwise 

 smooth ; segments 5-lobed ; basal and middle loljes twice dichotomous, their ultimate shal- 

 low subdivisions terminated by two, sometimes three, gland-like teeth ; end lobe eniarginate, 

 its angles dentate. Sporangium as in M. denticulata, but considerably smaller. (A.) 



M. ^rnniilafa, Wood (sp. nov.) 



M. magna, suborbicularis, arete granulata ; semieellulis quinqnelobis, lobis inter se sinu angnsto 

 discretis, basalibus et intermediis jjlerunique integris, lobo polari supra valde dilatato, in 

 dorso medio leviter retuso ; margiuibus valde crenatis. 



Diam.— hong, ^i/ = .0043". Lat. t^JVo" = -0030". 



Nab. — South Carolina, (Ravenel) 



Large, suborbicular, closely granulate; semicells 5-lobed, lobes separated by narrow sinuses; 

 basal and intermediate lobes mostly entire ; end lobe distally broadly dilated, broadly and 

 very shallowly emarginate ; margin of frond strongly crenate. 



Remarhs. — The only specimens of this species that I have seen were collected by 

 Prof. Ilavenel in a shallow ditch near Aiken, South Carolina, where they formed a 

 greenish, gelatinous mass, Avith numerons desmids and diatoms. It is most closely 

 allied to M. (nincakt, from Avliich it is separated by its entire lateral lobes, by its 

 granulated surface, and its crenated margins. It also does not apparently attain 

 as largo a size as that species. The grannies are very small in the central portion 

 of the frond, but become larger as they approach the margin. 



Fig. 16, pi. 21, represents an empty frond of this species, magnified 460 diam- 

 eters. 



M. Jenneri, Ralfs. 



M. magna, oblonga, ]ilornniquc siibfilitcr granulnta ; semieellulis quinquelobis; lobis basalibus 

 et intermediis cequilatis, confertis, cuneatis, bilobulatis ; lobo polari late truncato vel late 

 rotundato, in medio intcrdum leviter et obtuse emarginato, interdum nonnihil profunde eraar- 

 ginato. 



Diam.—Uii. 4SJ'— 1/506'''= OOG"— .0062". Long. ^fS/—- rsVu/ = .00G2"_.0081", 



