XI LEPTOSPORANGIAT^ HETEROSPOREM 421 



four hours for its completion. Pilularia approaches much nearer 

 to the Polypodiaceas in the structure of the antheridium (Fig. 

 246). The first funnel-shaped wall is much more frequently 

 extended to the basal wall, and the two groups of sperm cells 

 are much less distinct than in Marsilia. 



The spermatqzoids of Marsilia are at once distinguished 

 by a great number of coils, sometimes thirteen or fourteen in 

 M. vestita. The cilia are very numerous, but are attached only 

 to the broad lower coils, the upper narrow ones being quite free 

 from them. The vesicle attached to the broad lower coils is 

 very conspicuous and contains numerous starch granules as 

 well as albuminous ones. In Pilularia the long upper part of 

 the spermatozoid is absent, and it apparently corresponds only 

 to the few broad basal coils of that of Marsilia, which are of 

 nuclear origin, like the 

 greater part of the body 

 in the spermatozoid of 

 Pilularia. 



Shaw (3) and Belajeff 

 (7) have studied the de- 

 velopment of the sperma- 

 tozoid in Marsilia, Shaw's X'—V v^.y-.v 

 studies on M. vestita be- „ ^ u- .,. j- c d. ; ■ , ^ 7- 



Fig. 246. — Ripe antheridium of Pilulana globuh' 

 ing especially complete. fera, showing the two vegetative prothallial 



At the close of the sec- 'f"-^"\u\ '^"''' m '^^ ^?"'"f'°^°"^' 



showing the large vesicle K.V) with the con- 

 Ond from the last division tained starch granules. 



of the central tissue of the 



antheridium, there appears at either pole of the spindle a small 

 body, the "blepharoplastoid," which seems later to divide, the 

 two halves increasing in size and remaining together near the 

 resting nucleus. These two blepharoplastoids seem to disap- 

 pear during the early stages of the next mitosis, but shortly 

 afterwards there is seen at either pole of the spindle a small 

 blepharoplast (&). At the close of the mitosis the blepharo- 

 plast lies near the nucleus of the cell (the secondary sperma- 

 tocyte of Shaw) . This blepharoplast divides, and the daughter 

 blepharoplasts increase in size, finally occupying a position near 

 the poles of the nuclear spindle (Fig. 247, B). This division 

 results in the formation of the spermatozoid mother cells, or 

 spermatids. 



After the division into the spermatids is complete, the 



