418 Wilson . — Spermatogenesis in the Bryophyta . 
of the spermatozoid. Both in the Hepaticae and Filicineae he described 
a red-staining contractile ground substance surrounded by a non-contractile 
spirally arranged skin which takes up the blue stain. This structure per- 
sists in the mature spermatozoid. The development in Aneura and Mar - 
chantia polymorpha is similar in most respects. In the latter plant a centro- 
some is present at each pole of the spindle during the division of the 
spermatogenic cells ; in the mother-cell two bodies, probably centrosomes, 
are found, and these persist in the spermatozoid near the place of attachment 
of the cilia. 
Strasburger ( 62 ) in 1892 was unable to identify the structures de- 
scribed by Schottlander. In Pellia calycina he found that the cilia are 
attached some small distance behind the anterior end of the body of the 
spermatozoid. On staining with a mixture of iodine green and fuchsin the 
middle part of the body becomes blue, while the anterior portion, cilia, and 
posterior plasma mass take up the red stain. Marchantia polymorpha and 
Polytrichum commune also agree in this staining reaction. The anterior 
cytoplasmic portions of the spermatozoids of Chara and Pellia are homo- 
logous, but in the latter this portion remains short ; on the other hand, the 
posterior cytoplasmic process is not present in the Muscineae. In other 
respects there is a great correspondence between the spermatozoids of the 
two groups, and the resemblance also extends to their development. In 
Pellia calycma the mother-cells remain together in pairs even when forced 
out of the antheridium. The nucleus elongates considerably, so that it finally 
reaches quite to the posterior end of the body. A strongly refractive 
Cytoplasmahbcker ’ appears at the side of the nucleus, and this forms the 
short anterior portion which bears the backwardly directed cilia. A vesicle 
such as occurs in the Filicoideae is not present, but the cytoplasm is spread 
along the length of the spermatozoid. Strasburger agrees with Guignard 
that the body is not completely enclosed in a thin cytoplasmic layer. 
After Strasburger’s discoveries in 1892 a considerable period elapsed 
before the appearance of further investigations on the Bryophyta, although 
several important papers were published on the spermatogenesis in other 
groups. During this period Campbell ( 17 ) noted the rectangular ‘ sperm 
cells ’ of Fimbriaria Calif ornica and described and figured the walls sepa- 
rating the spermatozoids of Funaria hygrometrica i which still persist after 
ejection from the antheridium. Miyake ( 45 ) also described the spermato- 
zoids of Makinoa crisp at a, which, are the largest yet discovered in the Hepa- 
ticae. He figures an antheridium showing the rectangular spermatogenic 
cells, and the spermatozoids are shown still enclosed with the walls of the 
mother-cells. 
Ikeno’s ( 32 ) work in 1903 was carried out with modern cytological 
methods and was the first detailed description of spermatogenesis in the 
Bryophyta. He confined himself to the investigation of Marchantia poly - 
