'34 



ARCHEGONIATES. 



is formed, a small eccentric body appears in each blepharoplast (Fig. 

 53, D), then several, so that it appears as if the blepharoplast had 

 broken up into a group of small bodies (Fig. 54, E). Out of these 

 bodies is developed the band, which elongates, and together with the 

 nucleus moves toward the plasma membrane of the cell (Fig. 54, F, G). 

 In cross section the band is broadly U-shaped, but when seen from 

 above it appears as a double line (Fig. 54, H). The band continues 

 to elongate until finally a spiral is formed, which makes five or more 

 turns about the hemispherical half of the cell (Fig. 54, I). The 

 nucleus also elongates, becoming sausage-shaped, and lies in close 

 contact with the larger turns of the blepharoplast. The mature sper- 

 matozoid in Marsilia is composed, therefore, of a blepharoplast, 



FIG. 53. Blepharoplast primordium during division of grandmother-cell of spermatozoid in 

 Marsilia vestita. (After Shaw.) 



A, the two primordia of the blepharoplasts lie in cytoplasm some distance from nucleus. 



B, they are now on opposite sides of the nucleus but a little to one side of median line. 



C, the nucleus is in spindle stage of division; the young blepharoplasts lie near the respective poles of 



spindle. 



D, telophase of division; blepharoplast rudiment at pole of each nucleus contains a dense granule. 



consisting of a funnel-shaped spiral of about ten or more turns, and a 

 sausage- shaped nucleus without a definite visible structure, which is 

 connected with the three larger posterior turns of the blepharoplast 

 (Fig. 52, B). The posterior end of the blepharoplast, which is usually 

 bent in the shape of a hook, extends beyond the nucleus. The rela- 

 tively large vesicle is embraced by the larger posterior turns of the 

 blepharoplast. In Marsilia vestita the author observed that the 

 vesicle remains adhering to the spermatozoid for a longer time than in 

 Onoclea struthiopteris. The vesicle consists of a delicate cytoplasmic 

 reticulum, in which are held large starch and protein granules. The 

 numerous cilia (the spermatozoids were fixed and stained upon the 

 slide) spring from the middle and posterior coils, the two or three 

 anterior coils being free from them. In some cases observed the cilia 

 extended almost to the posterior end of the blepharoplast. As soon 

 as the vesicle drops off, the spermatozoid becomes much elongated, 

 losing its pronounced funnel-shape. 



