EXPLANATION OF THE PLATES. 259 



Fig. 15. Coamarium Broomei, Thw. Front view, magniCccl 4fi0 diameters. 

 Fig. 16. Cosmarium commissurale, Breb. Front view, magnified TSO diameters. 

 Fig. 17. Xanthidium armatum, Breb. Front view, magnified 2G0 diameters. 



PLATE XIV. 



Fig. 1. A sterile cell of Ehynehonenia elongatum, Wood, magnified 4.50 diameters. 

 Fig. 1 a. Portion of a filament containing a fertile cell, with the spore nearly matured, amiiliUed 

 450 diameters. 



Fig. 2. A filament of Bhynelioncma pulchcUum, Wood, containing both fertile and sterile cells, 

 magnified 2G0 diameters. 



Fig. 3. The ripened spore of Bpirogyra protecta, Wood, magnified 450 diameters. 



Fig. 3 a. Outline of conjugating filaments, and figure of a sterile filament, enlarged 250 diameters. 



Fig. 4. Sterile cells of Spirogyra longala (Yauch.), magnified 250 diameter.?. 

 Fig. 4 a. Fertile filaments, magnified 200 diameters. 



Fig. 5. A filament of Aphanocheete rcp)cns,\^ ooA, which has lost its cilia, magnified 400 diameters. 



Fig. 6. A fertile branch of Draparnaldia BilUngsii, Wood, showing the chains of spores, mag- 

 nified 4C0 diameters. 



PLATE XV. 



Fig. 1. Portion of a filament of Spirogijra mnjii^cula, Ktz., containing cells with mature spores 

 and others just commencing the process of conjugation. 



Fig. 2. A portion of a sterile filament of Spirogyra dilula, Wood, magnified 125 diameters, also 

 the outline of a pair of conjugating filaments of the same ann)lifieation. 



Fig. 2 b. Conjugating filaments of Spirogyra dilula, Wood, magnified 125 diameters. 



Fig. 3 a. Portion of a sterile filament of Spirogyra sfcliformis (Roth) Ktz., magnified 125 

 diameters. 



Fig. 3 b. Conjugating filaments of the same species, similarly amplified. 



Fig. 4 a. Cells of Spirogyra crassa, Ktz., preparing for conjugation. 



Fig. 4 c. Conjugating cells of the same plant in the first stage of union. 



Fig. 4 b. Conjugating cells containing nearly matured zygospores, enlarged 125 diameters. 



Fig. 5. Filaments of 3Iesorarpus scalaris, Hassall, eumnieneing the process of conjugation, mag- 

 nified 125 diameters. 



Fig. 6. Sterile cells of Spirogyra insignis (Hassall) Ktz. 

 Fig. 6 6. Conjugating filaments of the same species. 



Fig. T. Conjugating filaments of Spirogyra pariispura, Wood, containing nearly matured 

 spores, magnified 125 diameters. 



Fig. 8. Portion of an ordinary sterile filament of Zygnema insigne (Hassall) Ktz. 

 Fig. 8 a. Fertile filaments of the same, magnified 250 diameters. 



Fig. 8 6. Sterile filament in which multiplication of the species is taking phice by the separation 

 of the cells, magnified 2G0 diameters. 



PLATE XVI. 



Fig. 1 a. Cells of Sirogonium retroversum,^ ooA, just commencing the process of conjugation. 



Fig. 1 b. Sterile cells. 



Figs. 1 d and 1 c>. Outlines of fertile cells; all of these figures are magnified 2C0 diameters. 



