FRESHWATER ALGÆ FROM CAUCASUS AND TURKESTAN. 135 



32. Closterium lanceolatum Kütz. 

 Wladikaokas — Kasbek, long. 455 /r, lat. 6'i f.t. 



33. Closterium strigosuni Biéb. forma. 



It seems to be an intermediate form between Gl. strigosum 



and CI. peracerosum Gay. 



Wladikaokas — Kasbek, long. 190 /<, lat. 18 //. 



34. Closterium peracerosum. Gay. 



Mleti — Douchet. long. 228 /t; lat. 15 /t. 

 35 Closterium littorale Gay. forma. Pl. II Fig. 13. 

 Wladikaokas— Kasbek, long 248 /<; lat. 30«. 



Genus Cosmarium Corda. 



36. Cosmarium undulatum Corda. 

 Wladikaokas — Kasbek. 



36a. var. minutum Wittr. 



Wladikaokas — Kasbek, long. 28 f.i ; lat. 20 (.i ; lat. isthm. 7,5 f.i. 



37. Cosmarium tenue Arch. 



Wladikaokas — Kasbek, long. 15 (.i; lat. 12 /<; lat. isthm. 4/4. 



38. Cosmarium granatum. Bréb. 

 Kasbek — Mleti. 



38a. var. depressum nov. var. Pl. II Fig. 15. 



Differs from the typical form in being shorter, ratio of 



axes 1,4 : 1. The apices are also considerable broader. 



Dimensions of cells : 



long, 17/<; lat. 12,5 /<; lat. isthm. 4,5 /r, crass. S f.i. 



I am in some doubt, if the form should really be referred to 



Cosmarium granatum. It seems in many respects to be 



an intermediate form between C. granatum and C. subtu- 



midum. 



Askabad. 



39. Cosmarium subtumidum Nordst. 

 var minor nov. var. Pl, II Fig. 14. 



Cells small, a little longer than broad. Front view of the 

 semicells pyramidate-semicircular, basal angles rounded; 



