LIVEEPOOL FEESH WATEE ALG.E. 291 



Fig. 4. Portion of a branchlet of Chcetophora elegans, 



(d) zoospores each with two cilia leaving the 

 filament from alternate sides of contiguous cells, 



(e) showing an outer delicate cell- wall, X 400. 



Plate XVII. 



Figs. 1, 2, 3. Cijlindrospermum comatum, young trich- 

 omes, X 400. 



Fig. 4. Older trichomes with wall of spore thickened, 

 echinated and coloured brown, X 400. 



Fig. 5. Spores and heterocysts detached from trichomes 

 all having the heterocysts rayed with fine hair- 

 like structures, X 400. This condition prevails 

 also in the young trichomes. 



Fig. 6. An old spore and heterocyst, the rays shorter 

 and bent over the heterocyst, X 400. 



Fig. 7. A specimen from Cumberland ; spore thickened 

 and heterocyst rayed, X 400. 



Fig. 8. Volvocineae. A colony of four cells ; (a, b, c, d) 

 seen in four positions, X 400, (e) division of 

 each of the four into other four cells ; three cells 

 in stages of division the fourth still possessed of 

 cilia ; (f) two cells under higher power. 



Fig. 9. A form of Chlamydococcus pluvialis, slight 

 changes noted during twenty minutes observa- 

 tion, number seven exhibited a pair of fine, 

 long cilia, X 400. 



Figs. 10, 11. Apiocystis brauniana. Attached to Meso- 

 carpus parvulus. Cilia long, only a few shown, 

 (e) shows two gonidia just begining to develop, 

 X 250. 



