44 i 
Wilson. — Spermatogenesis in the Bryophyta. 
duced when the spermatid is cut in various directions. As already explained, 
when the spermatid is viewed from above or below, the outline is circular 
(Text-fig. i), and semicircular whenever it is viewed from the side (Text- 
figs. 2 and 3). Since the nucleus is not centrally placed, it is obvious that 
all sections taken perpendicularly to the plane wall will not be similar. 
Text-figs. 1, 2, and 3 represent diagram matically the appearances respec- 
tively seen when the spermatid is viewed in three planes perpendicular to 
one another. 
Text-fig. 2 shows the appearance when the spermatid is seen in 
optical section through the line 1, 1 (Text-fig. 1) in a plane perpendicular to 
that of the flat surface, and Text-fig. 3 when similarly seen in section through 
the line 2,2 (Text-fig. 1). Fig. 75, PI. XXXVIII, is an accurate drawing 
