A rchegonium ; and on Spermatogenesis in Poly trichum. 129 
4. The number of chromosomes is six, and there is no reduction 
of their number during the last division of the spermatogenic cells. 
5. During the reconstitution of the daughter nuclei the chromosomes 
show an end-to-end union, and by the development of anastomosing threads 
a simple reticulum is formed. The chromatin gradually leaves this reticulum 
and collects to form the central nucleolus-like mass. 
6. During the anaphase of the last division of the spermatogenic cells 
a relatively large particle of chromatin is generally detached from each of 
the daughter chromosome groups, and is passed out into the cytoplasm. 
7. Centrosome-like bodies occupy the poles of the spindle during 
the last division, but are not present during the earlier divisions. 
8. The centrosome-like particle persists in the spermatid and becomes 
the blepharoplast. 
9. An extra division was observed in two antheridia, and this is 
preceded by the division of the blepharoplast. The daughter particles did 
not in all cases occupy the poles of the spindle during this division. 
10. The young spermatid contains, in addition to the nucleus, a con- 
spicuous blepharoplast. The greater part of the chromatin is now passed 
from the nucleus into the cytoplasm and collects in the form of two spherical 
masses, which correspond to the single f Nebenkorper 1 of Ikeno. 
11. An arched band-like organ is next developed, probably at the 
expense of the extruded chromatin bodies, one of which is consumed 
in the process. This band passes round the periphery of the spermatid and 
joins the blepharoplast, thus connecting this body with the remaining mass 
of extruded chromatin. The nucleus is enclosed within the arch. 
12. The nucleus of the spermatid becomes drawn out along the arched 
band and the greater part of the latter is reabsorbed by the nucleus. 
13. The nucleus undergoes further elongation to form the body of the 
spermatozoid, which ultimately occupies about one and a half turns of 
a spiral. At the anterior extremity occurs a minute particle which is 
probably the remains of the blepharoplast, and in the region of this particle 
the two long cilia are inserted. At the posterior extremity of the spermato- 
zoid is a conspicuous vesicle which consists mainly of the remaining spherical 
mass of extruded chromatin. 
14. In the presence of water, the ripe antheridium extrudes a mucila- 
ginous mass, in which the spermatozoids are imprisoned. Each spermato- 
zoid rapidly revolves within a spherical vesicle, possessing a somewhat 
tenacious wall, and in laboratory experiments the spermatozoids rarely 
succeeded in making their escape from their vesicles. 
The University, 
Leeds. 
K 
