SPECIES OF DESMIDS. 8l 



5. LEPTOZOSMA. 

 An immature form of Desmidium, 6. 



6. DESMIDIUM. FIG. 6. 



i. Mucous sheath present cylindricum, 25 



i. Mucous sheath absent (a). 



a. Cells united by their entire end margins (b). 



a. Cells united by the outer portions of the ends (d). 



b. Cells nearly twice as long as broad longatum, 26 



b. Cells less than twice as long as broad (c). 



c. Cells in side view quadrate . quadratum, 26; quadrangulatum, 27 



c. Cells in side view triangular Swartzii, 26 



d. Borders crenate or undulate . . aptogonium, 27; diagonum, 159 

 d. Borders straight, filament twisted Baileyi, 27 



7. PHYMATODOCIS. FIG. 7. 



One species Nordstedtianum, 28 



8. SPH^EROZOSMA. FIG. 8. 



i. Cells twice broader than long, lobes not constricted (a). 



1. " " " " lobes constricted near the end, 



constrictum** 



2. Cells twice longer than broad, in sheath or not . excavatum, 29 

 2. Cells less than twice longer than broad (b). 



a. Cells closely approximate, ends rounded .... pulchrum, 29 

 a. " " " ends truncate, concave, rectangulare, 31 



a. Cells more or less remote, ends rounded . . . vertebratum, 30 



b. Ends pointed; semi-cells remote; sinus deep, wide, momltforme** 

 b. Ends rounded, spinous; cells slightly constricted, spinulosum^ 31 

 b. Ends rounded, not spinous; cells deeply constricted, filiforme^ 29 



b. End truncate, concave Wallachii, 30 



b. Ends truncate, not concave pulchellum** 



9. ONYCHONEMA.* FIG. 9. 



T. Cells with spine-like projecting ends serratum, 30 



2. Cells without spine-like ends Nordstedtianum.\ 



10. MESOT^ENIUM. FIG. IO. 



i. Cells cylindrical (a). 



i. Cells oval or elliptical, about twice longer than wide, in mucus on 

 wet wood . micrococcum, 32 



*Mr. Wolle joins this to Sphcerozosma. \ Journ. R. Micr. Sec., Dec., 1885. 

 **F.-w. Algae, .pp 23 et seq. 



