687 
Residual Nebenkern going towards the lumen of the tubule, the chro- 
matic body towards the root of the tail, where together with the 
centrosomes (fig. 4b) they become enfolded by a delicate membrane 
forming a collar (fig. 4h) to the still colourless elongating nucleus. 
The chromatic body now separates into two portions of unequal 
dimensions, both of which are reabsorbed into the colourless nucleus, 
which consequently, under the action of reagents, is seen more and 
more intensely stained. 
During all this, the delicate collar wrapped round the tail and 
the centrosomes becomes thickened, and elongated, on one side, assuming 
Fig. 3. Fig. 4. 
a form like that of a cheese scoop (fig. 4h). The tail passing down 
as a central axis and terminating basally, just where the margins of 
the expanded collar converge into the rechromatised nucleus forming 
its conical base. 
The head of the spermatozoon is now almost fully formed and 
during its maturation the tail has become immensely elongated; the 
Residual Nebenkern together with a degenerating mass of kytoplasm 
has moved away along the tail towards the lumen of the tubule, where 
it separates, and breaks down as the well known residual corpuscle, 
leaving the delicate tail of the spermatozoon free. 
