BATRACHOSPERMUM. 



117 



With the process of fecundation as the primary object in view, 

 Batrachospermum has been recently studied by Davis ('96), Schmidle 

 ('99), and Osterhout (1900). As regards the cytological details 

 bearing upon fecundation the work of Osterhout seems to have been 

 the most thorough. 



The well known female sexual organ, the carpogonium, of Batra- 

 chospermum, is a single cell consisting of a somewhat flask-shaped 

 basal part, the trichophore, in which is the egg-nucleus, connected by 

 a narrow neck to the elongated, cylindrical or club-shaped, upper 

 part, the trichogyne (Fig. 45, B). In B. boryanum Sirodot, the 

 species studied by Osterhout, the chromatophore of the trichophore 

 is continued into the trichogyne. The structure of the nucleus is 

 the same as that of higher plants. The spermatia are globular cells 



with one nucleus and a 

 reduced chromatophore 

 in younger stages (Fig. 

 ^ 45, A). 



FIG. 45. Sexual organs of Batrachospermum boryanum 

 Sirodot. (After Osterhout.) 



A, antheridium with one nucleus and vactiolale cytoplasm. 



B, mature carpogonium before fecundation. 



C, spermatium has copulated with trichogyne of carpogo- 



nium ; cytoplasmic fusion has taken place, but nucleus 

 is still in spermatium ; egg-nucleus lies in tricho- 

 phore. 



Schmidle ('99), whose observations were made chiefly upon B. 

 bohneri, agrees with Osterhout as regards the structure of the carpo- 

 gonium, but in the spermatia of this species he finds, almost invariably, 

 two nuclei. Davis ('96), differing from both Schmidle and Osterhout, 

 claims that in B. moniliforme Roth., B. ccerulescens Sirodot, and 

 B. boryanum, the trichogyne is a distinct cell possessing a well defined 

 nucleus and chromophore, and connected with the trichophore by a 

 strand of protoplasm. The methods used by Davis at the time were 

 inadequate for the better differentiation of the nucleus, and his con- 

 clusion is in all probability incorrect. 



The copulation of the spermatia with the trichogyne and the fusion 

 of the sexual nuclei is as follows : One to several spermatia, which are 

 now provided with a cell-wall, become attached to the trichogyne 

 chiefly near the end (Fig. 45, C, and Fig. 46, D, E). After the disso- 

 lution of the cell-membranes at the point of contact the nucleus of the 

 spermatium enters the trichogyne and passes down through it into the 

 base of the carpogonium. The canal between the trichogyne and the 



