342 HOFMEISTER, ON 



Sometimes the moieties of the primordial utricle fill the 

 mother-cell entirely ; the cell-walls secreted by them then 

 appear — so far as they correspond with the surfaces of 

 contact of two halves of the primordial utricle — like septa 

 seated upon the inner wall of the spore (PI. XLVI, fig. 9).* 

 More frequently however the division of the cell-contents is 

 accompanied by a contraction! of them into a smaller space ; 

 the daughter-cells, which are of a flatly ellipsoidal form, lie 

 free in the interior of the spore. Numerous very small 

 amyloid granules now appear in the fluid contents of the 

 daughter-cells. Each of these cellules produces in its inte- 

 rior one or two lenticular vesicles, in each of which is pro- 

 duced a thread, rolled up in a right-handed spiral, and 

 consisting of a substance rendered brown by iodine (PL 

 XL VI, fig. 11). One of its ends is somewhat thickened, 

 the other is drawn out into a thread-like termination. 

 When perfect, the spore and its daughter- cells are ruptured 

 by the swelling of the contents ; the lenticular mother- 

 vesicles of the spermatozoa become free in the opened cavity 

 of the spore. Soon the membrane of the vesicle itself — 

 which is rendered blue by iodine — is ruptured ; one end of 

 the spermatozoon protrudes from the fissure, and immediately 

 commences an active oscillatory motion, which causes a rapid 

 revolution of the mother-vesicle (PI. XLVI, fig. 12). Ulti- 

 mately the spermatozoon frees itself entirely from the vesicle, 

 and the turns of the spiral separate somewhat from one 

 another. It slips out of the ruptured spore, maintaining a 

 constant revolution round the axis of its spiral, and moves 

 about in the water with the thick end in front, dragging the 

 thinner one after it (PI. XLVI, figs. 13 — 15). Its motions 

 are slightly more rapid than those of the spermatozoa of 

 mosses 4 



If the spermatazoon be killed with iodine, a small number 



* Spores thus divided are exactly like the small ellipsoidal cellular bodies 

 which burst forth iu the spring from those sporangia of Sahinia nutans which 

 produce microspores, i. e., the cellules iu whose chambers the mother-vesicles 

 of the spermatozoa originate. 



f Analogous to the process occurring in the spore-formation of liverworts 

 and mosses (Pellia and Phaseum). 



% Mettenius,_ who discovered the spermatozoa of Isoetes, remarks upon the 

 slowness of their motion compared with the rajaid motion of the spermatozoa of 

 ferns. 



