MUNSON: SPERMATOGENESIS OF PAPILIO. 
101 
plate 14, figure 47. A similar section through the centrosomes is 
represented in plate 14, figure 42. The large nucleus of the large 
nurse cell sometimes occupies an eccentric position, and hence it is 
visible in transverse sections. The loose arrangement of the cyto- 
reticulum of the head nurse-cell is seen to the left in figure 42. 
Further Growth and Modifications. 
It seems that the chromatin substance within the greatly elongated 
nucleus of the spermatozoon can shift its position. Instead of being 
pulled out lengthwise as in figure 44 (pi. 14) it may condense near 
the base of the head nurse-cell as in figure 43. I infer that this repre¬ 
sents a more advanced stage than figure 44. This same condensa¬ 
tion appears in figure 48, a stage still more advanced. 
The mature stage is probably that represented in figure 54 (pi. 14). 
In all of these cases the row of centrosomes is visible. In the later 
stages (pi. 14, fig. 48) the centrosome appears elongated, the vacuole 
in which it lies having also assumed an oval form. 
The greatly elongated nucleus shows distinctly that it is not homo¬ 
geneous, but composed of granules, probably the chromosomes con¬ 
siderably reduced (pi. 14, fig. 48). 
The discharge of mature spermatozoa .— When a spermatocyst is 
mature, the lateral cyst cells gradually dissolve. This takes place 
just as the cyst is about to enter the vas deferens. The spermatozoa 
then escape in a bundle into the vas deferens. Occasionally they are 
discharged into the follicle of the testis one by one (pi. 14, fig. 51). 
In that case they show a tendency to associate in bundles forming 
rings (pi. 14, fig. 53). These appear occasionally to become im¬ 
bedded by their heads into an unripe gonocyst causing a gradual 
degeneration of those cells (pi. 14, fig. 45). In the vas deferens the 
spermatozoa are frequently found in bundles, and even still attached 
to the partly disorganized head nurse-cell. They usually separate at 
once, on entering the vas deferens, and probably under the influence 
of its secretions become wavy and coiled—the only evidence of move¬ 
ment I have seen (pi. 14, fig. 55). 
The elongated head now becomes considerably shortened and bent 
into the form of the letter S, the centrosome forming an enlargement 
of the anterior filament. In many cases the tail forms a loop just back 
