DR. JULIUS SCHAAESCHMIDT ON AFGHANISTAN ALGjE. 247 



f. 9), et a G. microsphincto, Nordstedt, f. parvula, Wille (Fersk- 

 vandsalger fra Novaja Semlja, p. 38, t. xii. f. 22), praecipue semi- 

 cellulis vertice oblongo elliptieis medio breviter cuspidatis. 



36. Cosmaeium pyramid atum (Ralfs) , Brebisson ; Be Notaris, 

 Mementi per lo studio delle Desmidiacee Italiche, p. 40, t. iii. f. 22. 

 Size 0-040 X 0-030 millim. 



37. C. grastatum, Brjbisson ; Ralfs, British Besmidiacece, 

 p. 96, t. xxxii. f. 6. Size 0040 X 0*030 millim. 



Var. elongatum, Nordstedt, Besm. Spetsberg. t. vi. f. 6. With 

 zygospores. Size 0*036 X 0024 millim. ; zygospore 0*028 millim. 



38. C. abruptum, Lundell, Be Besmidiaceis qucs in Suecia 

 inventce sunt observationes criticce, p. 43, t. ii. f. 22. 



Forma nov. simplex; semicellulis verrucis centralibus desti- 

 tutis. (Plate V. fig. 24.) Long. 0-019 millim., lat. 0*015 millim. 



39. C. Meneghinii (Meneghini), Brebisson ; Be Bary, Conju- 

 gate^ t. vi. f . 46. Size 0*015 x 0*011 millim. 



40. C. minutum, Belponte, Specimen Besmid. Subalp. ii. 

 p. 105, t. vii. f. 37. Size 0028 x 0020 millim. 



41. Ciosterium Cornu, Ehrenberg ; Ralfs, British Besmi- 

 diacece, p. 176, t. xxx. f . 6. Size 0*120 X 0*006 millim. 



42. Desmidium quadratum (Belponte), mihi ; Bclponte, Spe- 

 cimen Besmid. Subalp. i. p. 63, t. iii. f . 20-23. 



Var. nov. excayatum ; semicellula) vertice visae duobus latcribus 

 excavatis ; taeniis chlorophyllaceis quattuor. (Plate V. fig. 25.) 

 Long. cell. 0*023 millim., lat. 0024 millim. 



Zygnemacej). 



43. Mougeotia sp. ? The conjugated filaments of this Mou- 

 geotia were soaked for a few minutes in warm water. By this 

 treatment the cell-walls of those either in conjugation or about 

 to become so, swelled iu such a manner as to occupy the cell- 

 cavity, and compress the dry contents of the cells, the primor- 

 dial utricle, the irregular chlorophyll, and imbedded starch- 

 granules (Plate V. fig. 13). The vegetative cylindrical cells 

 exhibited no alteration (Plate V. fig. 14). 



When the filament is stained with iodine (in alcohol), it is 

 seen that the swollen cell-wall is distinctly composed of layers ; 

 by the action of alcohol (extracting the water) thejayers of the 



