COLEOCH^ETE. 91 



figure, consists merely of the liquified or gelatinized remains of the 

 lamella. 



The spermatozoid, contrary to male gametes among the algae, bears 

 a circle of cilia at its anterior end (Fig. 31, A). It is not known 

 whether the cilia are developed from a distinct body or blepharoplast, 

 or whether the cilia-bearer is only a thickening of the plasma mem- 

 brane, as Strasburger maintains for the asexual swarm-spore of this 

 genus. Near the posterior end of the spermatozoid lies its small and 

 dense nucleus, in which a nucleolus is not to be recognized. 



Soon after the spermatozoid enters the egg, probably at the receptive 

 spot, its nucleus wanders toward the egg-nucleus (Fig. 31, D, E, F). 

 Before the final fusion of the two nuclei, that of the spermatozoid 

 increases somewhat in size (from 4/4 to 6/z) and becomes looser in 

 structure, but a nucleolus was not seen in it. After fusion has taken 

 place, the fact can be readily recognized in that the chromatin elements 

 of the male nucleus are distinguishable in the egg-nucleus. Very 

 soon, however, this characteristic disappears; the male chromatin 

 granules become distributed beyond recognition among those of the 

 egg-nucleus, since both nuclei are in the resting condition. 



COLEOCH^TE. 



Coleochaete demands a special consideration not only on account 

 of the peculiarity of the sexual organs but also because this remarkable 

 plant, owing to the behavior of the oosphere subsequent to fecundation, 

 may be regarded as a phylogenetic guide-post, which enables us to 

 connect with each other different groups of thallophytes, and which 

 indicates the probable course traversed by the ancestors of the lower 

 archegoniates. 



The recent studies of Jost ('95) and especially those of Oltmanns 

 ('98) have confirmed the classical account of Pringsheim ('58, '60) 

 with the addition of clearing up certain obscure cytological details, 

 which was possible only with the aid of more improved technique. 



In the development of the antheridium a small protuberance is 

 formed from the end cell of a filament, into which passes a daughter- 

 nucleus resulting from the division of the nucleus of the mother-cell, 

 and which is cut off by a wall formed at the junction of the protuber- 

 ance and the mother-cell (Fig. 32, A). No part of the chloroplast of 

 the mother-cell passes into the antheridium. In addition to this central 

 antheridium, others will be formed from the mother-cell in like manner, 

 so that finally several antheridia stand side by side at the end of the 

 mother-cell as so many branches (Fig. 32, B). The spermatozoids, 



