. 



248 DB. JULIUS SCHAAB8CHMIDT ON AFGHANISTAN ALGJB. 



cell -wall will be contracted. We see, then, that the cell-wall 

 is composed of three parts (Plate V. figs. 15 and 16) [exclu- 

 ding the common coat of the cells, the cuticle by which all the 

 'cells of the filament are uninterruptedly covered (Plate V. 

 fig. 16 a)~\, viz., the inner and outer thickened portion (Plate V. 

 figs. 15 a, b, and 16 b, c), and between these the exceedingly 

 translucent and easily seen portion. By this simple method I 

 have found a constant difference between the fertile and sterile 

 cells of this Mougeotia. 



Size : vegetative cells 0*020 millim., l|-5 times as long ; zygo- 

 spore (Plate V. fig. 17) 0-028x0-036 millim. 



44. Spibogyba mieabilis {Hassall), Kutzing ; Petit, Spirogyra 

 des Environs de Paris, p. 14. t. iii. f. 4. Some zygospores are 

 cylindrical and rounded at the ends as in S. lutetiana, Petit. 

 Size : zygospore 0-084 x 0-032 millim. (1 : 2|). 



45. S. pobticalis (O. jP. Muller) ; Gleve, Svenska arterna 

 af Algfamiljen Zygnernacece, p. 22, t. v. f. 13 ; Petit, 1. c. p. 21 

 t. v. f. 9. Size : zygospore 0-056 x 0*028 millim. (1 : 2). 



46. S. punctata, Gleve, Svenska arterna af Algf. Zygnemacece, 

 p. 23, t. vi. f. 4. Size : zygospore 0-065-0075 millim. x 0-030- 

 0-033 millim. (1 : 2). 



PALMELLACE^. 



47. Pleubococcus mucosus, Kutzing ; Cooke, British Fresh- 

 water Algce, ii. p. 4, t. ii. f . 3. Size : cells 0*003 millim. 



48. Dactylococctts infusionum, Nageli in Oattungen einzell. 

 Algen, p. 85, t. iii. f. F. Size : cells 0-009 X 0004 millim. 



49. Ooctstis Nagelh, Alex. Braun. Eight-celled family. 

 Size : family 0-036 millim. ; cells 0-018 x 0*009 millim. 



50. Glozoctstis vesiculosa, Nageli; Cooke, British Fresh- 

 water Algce, i. p. 7, t. iii. f. 2. Size : family 0-050-0*070 millim. ; 

 cells 0-007-0-010 millim. 



PBOTOCOCCAOEiE. 



51. Peotococcus sp. ? Size: cells 0*036 millim. 



52. Poltedeium MINIMUM, Alex. Brawn, Lagerheim Bidrag 

 till Sveriges Algflora, p. 69, t. i. f. 27. Size : cells 0*006 millim. 



