Wilson . — Spermatogenesis in the Bryophyta. 429 
attained their greatest length two bodies are found within the nucleus pro- 
duced, as in the previous cases, by the division of the nucleolus (Figs. 23-5). 
These two bodies remain close together for some time, and this circumstance 
aids in the determination of the order of events. The rod-like bodies, which 
are at first distinct from each other, become massed together in the vicinity 
of a vacuole which, at this stage, is always found in the cytoplasm. They 
decrease in length and at the same time become thicker, and finally a deeply 
staining mass is produced apparently by the coalescence of the greater part 
of the bodies in question (Figs. 26 and 27). The mass so produced is 
of variable shape and size, but often approaches an ovoid form. Fig. 25 
probably shows an early stage in its production. All the rod-like bodies 
do not take part in its formation, but one or two remain free and are usually 
found stretching away from the mass towards the periphery of the spermatid 
(Figs. 26 and 27). At this time the nucleus is faintly distinguishable and 
still contains the two bodies formed by the division of the nucleolus, but 
soon almost all trace of it is lost. Changes take place in the deeply stain- 
ing ovoid mass which result in the formation of a body which, although 
variable in form, is always recognizable in the spermatid at this stage. In 
view of the remarkable form of this structure, as well as its constancy 
of occurrence, it has been considered advisable to distinguish it in some way. 
The name limosphere is therefore proposed. 1 
The limosphere is usually situated towards one end of the longer axis 
of the spermatid. When fully formed it consists of a hollow sphere 
enclosing a vacuole. Its structure can be most easily explained by a full 
consideration of its development. The deeply staining mass formed by the 
coalescence of the rod-like bodies (Fig. 26) becomes more definite in form, 
and soon an almost spherical solid structure is produced (Fig. 27). This 
then becomes divided into two parts. As seen in optical section a curved 
interspace appears near its periphery, separating off an inner spherical por- 
tion from an outer shell which is usually incomplete on the side towards the 
periphery of the spermatid (Fig. 28). The interior portion of the inner 
spherical body now begins to lose its staining capacity (Fig. 29), and soon 
the greater part of it takes up only the cytoplasmic stain (Figs. 32 and 33) ; 
the remainder in the form of a segment of a hollow sphere still stains 
similarly to chromatin (Fig. 30). A little later the whole of this internal 
body takes up only the cytoplasmic stain, and finally it completely dis- 
appears (Fig. 31). At the stage the outer shell alone remains, enclosing 
a vacuole which in some cases contains a few ill-defined granules. 
Although the course of events just described is the usual one, variations 
doubtless occur. In some cases it is probable that the outer shell referred 
to above is separate from the beginning, and is derived from one or more of 
1 \ifxos = hunger, a (pa i pa = sphere. The name limosphere was suggested by Professor 
Farmer, F.R.S, 
