302 Woodburn. — Spermatogenesis in certain Hepaticae . 
in the cytoplasm of the sperm cell, a dense body appears which grows out 
into a densely staining slender cord around one side of the cell. This 
densely staining cord is the blepharoplast and bears very near one end — 
the anterior end of the mature sperm — two cilia, while the nucleus draws 
out into a narrow band along the posterior region of the blepharoplast. 
So far I have not found that any work has been done on the spermato- 
genesis of Porella. The observance of large nuclear figures in this Liverwort 
suggested that it might be suitable for such a study. Accordingly material 
was fixed at various times in the chromic-osmic-acetic killing fluid as for- 
mulated by Mottier (’ 97 ). Antheridial branches were fixed entire. At 
almost any time of the year, especially when cool and damp, various stages 
in the development of the antheridia were found in acropetal succession on 
the same branch — from very small antheridia to almost mature sperms. 
But only occasionally were nuclei found in the process of division. Resting 
conditions may be of long duration, but the process of division seems to 
occur very rapidly. This fact is no doubt correlated with the ability of 
Porella to dry up for long periods and then revive with rapid cell-division. 
Along with Porella careful studies were made in the spermatogenesis of 
Marchantia and Fegatella. 
The material, after fixing ordinarily for about twenty-four hours, was 
washed, brought up through the various grades of alcohol, embedded in 
paraffin, and sectioned, for the most part two microns thick. The following 
combinations of stains were used : anilin safranin and gentian violet, usually 
without the orange G; Heidenhain’s iron alum-haematoxylin; anilin safranin, 
iron alum-haematoxylin, and gentian violet ; iron alum-haematoxylin and 
gentian violet ; and iron alum-haematoxylin and Bismarck brown. 
In what follows I shall discuss the mitosis in spermogenous tissue, 
the last, or oblique division, and the development of the sperm. 
Mitosis in Spermogenous Tissue. 
As already suggested, the spermogenous cells of Porella are usually 
quite large. Compare Fig. 3, PL XXV (Porella), with Fig. 27 (Marchantia) 
and Fig. 46 (Fegatella). In an early stage of the antheridium, the nucleus 
presents a large nucleolus surrounded by a clear space, and, nearer the 
nuclear membrane, an open linin network with scattered chromatin granules 
(Figs. 1 and 2). The cytoplasm is more or less alveolate or fibrillar in 
nature, and quite granular. The granules vary in size, number, and dis- 
position, as do also the vacuoles if present (Figs. 1 and 3). 
In early prophase the chromatin lumps are larger and more drawn out 
along the linin threads. More than one nucleolus may be present at this 
stage (Fig. 3). If the latter figure be compared with Figs. 4, 5, and 6 , it is 
evident that the chromatin continues to collect along the linin threads until 
a more or less irregular spireme is formed, which lies near the nuclear mem- 
