i i: i: s ii -\v ATI: u AI.<; i: .11 TIM: i \ ri K D STATES. v. 



:* single, segregate, swimming free, compressed, 3-4-8-anglcd, more or lew produced as to tln-ir 

 an^lc*, sometimes rudiuttly elongate, i-itlu-r entire or bifid; mostly armed, oblong-elliptical when 

 viewed laterally, at each end rounded ur subtrancutc. Cytiodrrm thin, smooth; chloropliyl mo.-ily 

 granular, M|iiully distributed through the n-11, sometimes mixed with reddixh oil-drop*. 

 Propagation unknown. 



Remark*. This genus was described 1>% Nirgeli in his "Gattungcn Einzelliger 

 Aluen," and, although 1 ha\e never seen any specimen of it, it claims a place- h 

 because one species ha> lieeii found iu this country by Prof. Builcy. 



P. eiiornir, ( HALTS) DB BABY. 



ni.-dii.-iiiii. angulis productia achroia profunde bilobis, nonnunquam rcpctito-bilobis, lobis 



mucroimtiv ( II ) 



l>iam. 0.0011" 0.001C". (R.) 



P. enonin; ( KAI.FS) DK BART. RABENRORST, Flora Europ. Algarum, Sect III. p. 62. 

 Mnura*trui enorme, KALFS, British Desmidieae. 



Hub. Florida. Bailey. 



" Frond irrrirular or quadrate, spinotis; end view three or four-lobed ; lobes broad, more or 

 ! -- iiKirjrinatc or bifid, and terminated by ppincs, which are either simple or branched. 

 Sometimes the front view differs but little from the end one, usually, however, there is a 

 slight constriction or sinus at the junction of the segments, but I have never observed any 

 difference in the endochrome at that part. The spines, which arc almost confined to the 

 anglc.s, are irregular, some simple and some branched. The end view has three or four broad 

 and very irregular lobes ; these are spinous and more or less emarginate, and frequently one 

 lobe is much broader and more spinous than the others. The spines on such lobe form two 

 groups, separated by the notch; they vary much in size and are either simple and subulate, 

 or else forked; sometimes the forked spines are again divided at the apex." 7.'u//V Jlriit.-k 

 Desmidiete, p. 141. 



Genus SCENEDESMUS, METEN. 



Cellulir polymorphic, utroque polo tcquales vel intequales, tuepe in cornu spiniforme product, in 

 Ktatc pcrfccto 2-16 aut in svriem simplicem aut parencliyrnatice arete conjunct a- et co3nobinm con- 

 .-ti'in i.i. - ; cytioplasmate initio homogcneo, postea granuloso, vesicula chlorophyllosa central! vel 

 MibliitiTuli 't siepe loci-llo achroo lateral! instructo. 



1'ropagatio fit cytioplasmatis divisione snccedanea, unde gonidia oriuntur, quac inlr.i ccllulnm 

 inatricalem jam in coenobium planum sese conjungunt et membrane matricalis ruptura vel dissolu- 

 prodeunt. 



In polymorphous, equal or unequal at the ends, often produced into a spine-like horn, in tlic 

 t state 2-16 closely conjoined, cither as a simple series or in a parenchyma-like manner so as to 

 f'.rm. a cepnobinm. Cytioplasm in the beginning homogeneous, afterwards granular, furnished with 

 a central or sublateral chlorophyllous vesicle, and often with a lateral transparent spot 



Propagation occurring as a succedanenm to the division in the cells, whence arise gonidia, which, 

 already within the mother-cell, join themselves into a ceenobiuin, and are finally set free by the rupture 

 and dissolution of the maternal cell-wall. 



Remarks. According to Unger, in the genus Scenerksmtts the cells never exist 

 singly, but always in families. 



Two of the species here described as representatives of the genus certainly do 

 not conform to this, for 1 have frequently seen them both separate and in coenobia 



13 My. 1879. 



