of the Spores in Spirogyra. 299 



The assumption, moreover, that these clear moving cells (PI. IX. 

 fig. 8 g) are really true spores of Spirogyrce, is not opposed to any 

 of our experience of the propagation of the Algse. We find an 

 analogy with the production of these moving cells in the forma- 

 tion of the third, probably likewise slowly moving form of 

 spores in Achlya, the germination of which I have actually seen. 

 Finally, they agree perfectly in essential points of form and 

 motion with other moving spores which have long been known 

 to germinate. 



EXPLANATION OF PLATES VIII. and IX. 



Fiqs. 1-3 are magnified 123 times ; figs. 4-8, 246 times ; figs. 9-1 1, 45 times ; 

 fig. 12, 345 times ; &nAfigs. 13 & 14, 180 times, and drawn from 

 nature. 



Figs. 1-11. Spirogyra jugalis. 



Ko. 1. Conjugated filaments with germinating spores. 



¥igs. 2 & 3. Germinating spores ; the germ-plants are stdl umceUular ; 

 their ends sticking in the spores are prolonged mto a rootlike 

 structure. The green coat upon the walls separates by tearing 

 in several places into spiral bands. 



Fig. 4. Conjugated cells with the mother-cells of the moving spores. 



Fig. 5. A resting spore which had remained a longish time in glycerine. 



Fiqs. 6 & 6 6. Such a spore after long digestion in potash. 



fig. 7. A similar spore with the contents transformed mto several small 



Fig 8. Filament-cells of a young Spirogyra; its contents have been trans- 

 formed into the mother-cells of moving spores ; part of these have 

 already escaped from the mother-cells, part are still m process of 

 formation, part are perfect, but still contained in the mother-cells. 

 All the filament-cells of these young Spirogyra, even the radical 

 cell, have had their contents metamorphosed in this way ; a, b, c, 

 d, e,f, g, & it, I, exhibit the successive stages of development of 

 the mother-cells and the moving spores. 



Fig 9. Conjugated filaments with germinating spores, in outline. 



Fig 10. Young germinating plants with the radical extremity m the spore. 



Fig. \\a,b, c. Young germinating plants with the cell-producing apex in 

 the cell. 



Fig. 12. (Edogonium tumidulum. 



Fig. 12 a, b, c, d, e. Moving spores of CE. tumidulum after their attach- 

 ment. 



a &c d. The hd is already separate all round ; the contents are 

 transformed into the supposed mother-cells of the second form of 

 moving spores. 



b. The contents are transformed into six movmg spores and a 

 number of small brown bodies. The movement (a real locomotion) 

 of the clear spores evident, though slow. No indication of a lid 

 yet ; the cell still completely closed. 



c. The same as b, but the number of moving spores greater, 

 and the places where the hd falls off already indicated. 



e. Empty spores with the lid open. 



