98 F R E S H- W A T E R A L G J-J OF THE UNITED STATES. 



aii-riisto, lobis iiia?fiualibns, basi plcruniqiie constrictis, in cornua subcrassa obtusa productis, 



centralibiis polygoiiis, in antica parto repaiidis. (R.) 

 Si/n.—F. ellqilirum, Hassal. Rabenhorst, Hora Europ. Algarum, Sect. Ill, p. 77. 

 Hub. — South Carolina, Georgia, Rhode Island, Bailey. 

 Cells varying in number and arrangement; outer cells suddenly contracted into two short, 



cylindrical, obtuse processes. L. 1-1764" to 1-90G"; R. 1-1515" to 1-1020". 

 (3, Trotesses of Hie lobes truncately emargiuate. (A.) 



P. Ehrenbei'g'ii, (Corda) Braun. 



P. coenobio et orbicular! ct oblongo, perfecte clause, e ccllulis 8 vel 16 composito et quadrate, 

 e cellulis 4, late cuncatis, profunde lobatis, e.xacte cruciatim dispositis formato ; cellulis peri- 

 phericis cuneatis a basi truneata ad apiccni usque concretis, profunde bilobis sinu angusto, 

 lobi.s sajpe oblique truiicatis, plus minus sinuato-excisis, angulis interioribus ad duplum lon- 

 gioribus, omnibus acutis vel breviter appendiculatis; cellulis centralibus aut singulis aut 

 pluribus (2-5-6 v. 8), omnibus flavo-viridibus, polygouis, uno latere repandis vel profunde 

 ineisis. (R.) 



Syn. — P. Ehrenbcrgii, (CoRDA,) Braun. Rabenhorst, Flora Europ. Algarum, Sect. III. p. 77. 



Hah. — South Carolina, Georgia, Florida, Rhode Island, Bailey. 



Frond minute ; cells eight (seven disposed in a single series round a central one), bilobed, 

 angular. L. 1-2900" ; B. 1-2500". (A.) 



P. simples, Meyen. 



P. cellulis peripherieis ovato-cuspidatis, 8-10-16 basi tantum concretis, circulum simplicem 

 • constituentibus, centralibus siB|)e nullis. (R.) 



Syn. — P. simplex, Meyen. Rabenhorst, Flora Europ. Algarum, Sect. III. p. 71. 



Monactiinis octonariux, Bailey, Smithsonian Contributions. 

 Sab. — South Carolina, Rhode Island, Bailey. 

 Var. — dtiodenni'ius. 

 Coenobio dathrato, cellulis peripherieis 12, centralibus 4, regulariter cruciatum dispositis. (R.) 

 S>/n. — Monactinus duodenarius, Bailey. 



Inner cells four, somewhat triangular, enclosing a central, quadrate vacant interval, and four 

 broadly lanceolate vacant intervals between them and the outer series, to which they are 

 united by their terminal angles, outer cells twelve, subovate, truncate below, much attenuated, 

 acuminate. (A.) 



Famly VOLVOCINEtE. 



Coenobia mobilia, globosa, subglobosa vel quadrangulo-tabulata, e cellulis viridibus cilia bina 

 agilia gerentibus, intus vesica duplici contractibili prsditis coiaposita, membraua (tegumento, 

 chlamyde) communi achroa hyalina plus minus ampliata involuta. 



Propagatio aut se.xualis, monoica vel dioica (adhuc in paucis tantum generibus probata) ; cellulis 

 coenobii aut omnibus aut quibusdam genus masculinum vel feminnm exhibentibus, illis in fascienlos 

 spermatozoideorum (autheridia), has in oosporas episporio inclu.^as, non mobiles commutatis, aut 

 non sexualis, gonidiis agilibus, (et niacrogonidiis et niicrogonidiis— etiam zoogonidia vocantur). 

 Macro- et microgonidia (celluliB primordialcs) cytioplasraatis divisione simultanea et multiplici orta; 

 priora nuraero definita (2-4-8-16, &c.), majora oblonga vel rotundata, polo antico plus minus rostri- 

 formi producta, ciliis binis per vesica; racmbranam exsertis, puncto (ocello Ehrberg. stigma) sanguineo 

 centrali vel parietal! et locellis (vacuolis) saepe binis contraetibilibus instructa; ultima numero indefi- 

 nita, multo minora, pallide vel sordide viridia vel luteola, apice ciliis instructa, plernmque jam intra 

 cellulam matncalem vivide vacillantia, postea membranie ruptura libcre erumpentia, examinantia. (R.) 



