DR. NELSON ON THE REPRODUCTION OF THE ASCARIS MYSTAX. 
569 
of an inch (figs. 21 to 26 b); while the breadth of the spermatic particles varies 
from g- Q^Q -oth to se^j oth of an inch, and their length from rr^th to y^th of an inch 
(figs. 37, 38/,^). 
The spermatic particles (figs 37, 38) have long been known, but their nature has 
not hitherto been fully determined. 
Cloquet, in his elaborate work on the Ascaris lumhricoides, mistook them for un- 
developed ova. More lately, Kolliker imagined them to be bundles of capillary 
spermatic filaments. 
Wagner believes them to form the tail only of the spermatozoon (figs. 14, 15 a ) ; 
while Reichert evidently did not recognise their function, as he makes a nucleated 
cell (fig. 17) his ‘‘ Reifes Saamen Korperchen.” 
Lastly, SiEBOLD conjectures these corpuscles to be spermatozoa, having seen them 
in contact with the ova, but appears to have gone no further into the investigation. 
That these flask-shaped bodies (fig. 38) are the mature spermatic particles cannot 
now be doubted, as we meet with them the highest in the oviduct of the female, 
while near the external orifice of the vagina none but nucleated cells, or cup-shaped 
nuclei only are seen. 
As already stated, I have never observed a spermatic particle forcing out the 
cell- wall, except at a very early period of its development (figs. 24 to 29) ; but when 
perfectly formed, it is set free by the total disappearance of the spermatic cell. 
Nothing then remains except a few granules surrounding the nucleolus (fig. 38 b, c ) ; 
and, although the cell-wall is very frequently lost much earlier, the development of 
the nuclear membrane, which constitutes the spermatic particle, seems to go on as 
long as any granules remain to be transformed. Wagner, therefore, is not correct 
in supposing these bodies to be mere tails, because they never project as such from 
the spermatic cells ; also, when they become free, it is by the total disappearance of 
the cell ; and lastly, because they alone are found highest in the oviduct. 
Again, speaking relatively, what immense spermatozoa these cells (figs. 21 to 36) 
would make, if the opinions of Wagner and Reichert were correct, from to 
y^th of an inch in diameter, or one third that of the ovum in the same animal! a 
circumstance altogether unparalleled. 
Neither do I see any reason to believe Kolliker’s statement, that the spermatic 
cells are formed four at a time, within a mother-cell (fig. 16), never having observed 
such an occurrence. 
The whole of the changes I have described may easily be traced by examining 
the uteri of the larger individuals, as in these impregnation has in all probability 
not occurred till very lately ; their size apparently depending on the non-evolution 
of fertile ova. 
However, from the delicacy and transparent nature of the spermatic cell, when at 
its greatest development, the very best microscopes must be employed in order to 
detect it. 
