566 
DR. NELSON ON THE REPRODUCTION OF THE ASCARIS MVSTAX. 
pressure (fig. 20 b). This (fig. 20 a) is the utmost development the semen undergoes, 
as long as it remains in the male organs. These granular envelopes (fig. 20 a) appear 
to perform the important function of preserving and preventing the enlargement of 
the spermatic cells contained within them (fig. 20 c), for sometimes, but very rarely, a 
spermatic cell may be seen, which having escaped from its granular covering, has 
swollen up to three times its former size (fig. 20 d), an occurrence which, if it hap- 
pened more frequently, would prevent their passage through the spiculee, whose 
calibre is only capable of admitting a single granular mass at a time. 
Although the further changes which the spermatic cells undergo take place within 
the female, and consequently totally unconnected with the generative apparatus of 
the male, for the sake of continuity and to prevent confusion, I shall treat of them 
here. 
On examining the uterine contents of a recently impregnated Ascaris mystax, a 
granular fluid is observed in which a number of nucleated cells are floating, but I 
have never been able to observe the granular masses already described as seen in the 
male. The disappearance then of the granular envelope (fig. 20 a, h) is the first 
visible change in the constitution of the semen, and can be accounted for in many 
ways. 
The loose granules are the debris of the cell cases ; while the nucleated cells 
(Plate XXVI. figs. 21-36) are simply the spermatic cells (fig. 20 c) much enlarged, 
apparently by the spontaneous imbibition of the surrounding fluid. By this enlarge- 
ment, a most beautifully transparent spherical cell (figs. 21, 22 a) is produced g-^th 
of an inch in diameter, enclosing, or rather having attached to its inner surface a 
round, discoidal nucleus (fig. 21 h), and within this a nucleolus (fig. 21 c), sometimes 
even two nucleoli. 
Before I describe, however, the transformation of these nuclei into spermatic par- 
ticles, it will be useful to examine cursorily the statements of others on the subject. 
Wagner and Leuckardt, in their article on Semen, in Todd’s Cyclopaedia, speak- 
ing of the Ascaris acuminata, say, “ the nucleus has at first a roundish shape 
(fig. 12 a), but gradually stretches itself more and more, and projects more or less 
outwards with its point (figs. 13, 14, 15 a); thus metamorphosing itself into the 
peduncle-like appendix of the spermatozoon, the body of which is formed from the 
persisting membrane of the seminal ceir’(figs. 12 to \b b). 
Kolliker states that these cells (fig. 16 a) are formed four at a time within other 
larger cells (fig. 16Z>); and that the elongated nuclei of Siebold and Wagner 
( figs. 14, 15 a) are mere bundles of undeveloped spermatozoa, whose form he sup- 
poses, but has never seen, to be capillary. 
Reichert, in his researches on the development of the spermatozoa of the Ascaris 
acuminata, indicates a spermatic cell containing a nucleus and nucleolus (fig. 17)- 
The cell increases in size (fig. 17 «), as does the nucleolus (fig. 17 c) ; but the nucleus 
becomes less definite, and retains its former size (fig. 17 b). 
