126 Walker. — On Abnormal Cell-fusion in the 
The ‘ Nebenkern ’ of Yamanouchi ( 24 ) in Nephr odium and the 
nucleolus-like body described by Webber (20) in Ginkgo are possibly homo- 
logous with the ‘ Nebenkorper ’ (Ikeno) or ‘ limosphere ’ (Wilson), and 
in the higher plants may have lost its original function, as the former 
authors agree that it takes no part in the formation of the spermatozoid. 
The final changes which take place within the spermatid of Polytrichum 
will now be described. When the arched band is fully developed, the 
nucleus undergoes a marked change in form. Fig. 36 shows an early phase 
of this change where the nucleus is drawn out into a pointed process which 
is directed backwards. This elongation continues and the nucleus becomes 
extended upon the arched band until its anterior rounded extremity 
reaches the blepharoplast (Figs. 37 and 38). This band-like organ, hitherto 
so prominent, now appears less marked (Figs. 37-9), especially that portion 
adjoining the thicker part of the nucleus (Fig. 38), and in some spermatids 
is seen to have completely disappeared from this region (Fig. 37). It seems 
probable that the substance of the curved band has been reabsorbed by the 
nucleus, which from this point onwards stains more and more deeply 
(Figs. 38 and 39). The process of elongation of the nucleus continues until 
it takes the form of a thick curved rod (Fig. 39). 
In Chara a structure somewhat resembling the arched band of Poly- 
trichum in form and in its relation to the nucleus is described by Mottier 
( 15 ), and is regarded by him as a blepharoplast. This interpretation seems 
impossible in Polytrichum , where the band disappears before the cilia 
are developed. A superficial resemblance is also seen between the curved 
band of the Polytrichum spermatid and the coiled band formed by the 
elongation of the blepharoplast, described by Yamanouchi in Nephr odium. 
The body of the developing spermatozoid continues to lengthen and its 
anterior end is carried into the region of the vesicle or persistent ‘ Neben- 
korper ’ attached to the opposite extremity of the spermatozoid. The 
blepharoplast, which has now lost its refractive character, is thus obscured, 
and its further fate is difficult to follow. At a later stage, when many 
of the spermatozoids which now bear cilia appear less closely coiled, each 
is seen to terminate in front in a minute slightly elongate particle, probably 
the remains of the blepharoplast, behind which is a narrow feebly stained 
region (Fig. 40). Occasionally the cilia could be traced to this terminal 
particle, but very few spermatozoids in the sections displayed this region 
sufficiently clearly to make a determination of the exact place of insertion 
possible. The body of the spermatozoid is now extremely slender and 
stains uniformly throughout. 
The spermatozoid has now completed its development and consists of 
a spirally coiled band derived from the nucleus, carrying a pair of cilia at its 
anterior extremity, and at the posterior end the remains of the deeply stained 
sphere or ‘ Nebenkorper ’ which was originally extruded from the nucleus. 
