DR. NELSON ON THE REPRODUCTION OF THE ASCARIS MYSTAX. 
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too opake to allow the germinal vesicle to be seen. d. The clear substance 
forming a distinct and clear outline or margin to the ovule. 
Fig. 52. An unfecundated ovule, which having entered the oviduct has begun to 
alter, c. The vitelline granules which have begun to coalesce, and have 
lost their granular character entirely, d. The margin of the clear sub- 
stance. 
Fig. 53. An unfecundated ovule, in which the vitelline granules have wholly disap- 
peared, their oily portion having run together into large globules, e. The 
large oil-globules thus formed, d. The margin of the clear substance still 
distinct. 
Figs. 54, 55. An unfecundated ovule further changed, by which the oil-globules have 
begun to disappear, and the colouring matter of the original vitelline gra- 
nules to approach the centre ; while the whole ovule has become enclosed 
in a chorion, c. The colouring matter of the vitelline granules, e. The 
oil-globules, f. The granular chorion of the unfecundated ovum, which 
is secreted by the oviduct. 
Fig. 56. An unfecundated or false ovum at its maximum degree of organization. 
c. The colouring matter of the vitelline granules collected into an opake 
or false yolk, but containing no germinal vesicle or spot. f. The granular 
chorion or shell so characteristic of the false ovum. o. The yolk-mem- 
brane, that, separating from the interior of the chorion, contracts on the 
colouring matter to form the spherical opake yolk. 
Fig. 57. A false ovum ruptured by pressure, c. The colouring matter, which, with 
a few oil-globules, formed the opake yolk. f. The granular chorion, o. The 
yolk-membrane. 
Fig. 58. An ovule during fecundation, c. The vitelline granules displaced by the 
application of a spermatic particle, d. The clear substance presenting a 
distinct margin all round the ovule, except where the protrusion of the 
granules has taken place, g. A spermatic particle which is on the point of 
entering the vitellus, being partially imbedded in its substance. 
Fig. 59. An ovule during fertilization, whose vitellus is much broken up by the sper- 
matic particles, c. The vitelline granules displaced by the spermatic par- 
ticles. g. The spermatic particles which are entering the substance of the 
ovule, h. The spermatic particles that have penetrated and become wholly 
imbedded in the substance of the vitellus. 
Fig. 60. An ovule during fecundation, presenting more than one rupture of the sur- 
face and more transparent than usual, b. The germinal vesicle, generally 
invisible at this period, c. Protiaided vitelline granules, g. Spermatic 
particles applied against the surface of the ovule, h. Spermatic particles 
that have entered the vitellus. 
Figs. 61, 62. Fertile ova, in which the penetration of the spermatic particles has 
