126 THE HELMINTHES. $ 117. 
cells; in the anterior portion, these cells are more numerous and begin to 
be surrounded by a granular vitelline substance, in which the primitive 
nucleated cells are still seen; these cells therefore, ought perhaps to be 
regarded as germinative vesicles. In front, these eggs, which are of a dis- 
coidal form, are arranged in a row, or are grouped closely around a rachis 
which traverses the axis of the ovary. In the Fallopian tube, which may 
be known by its less diameter, the eggs become more mature, and, having 
been surrounded by a double colorless envelope, pass into the base of the 
uterus.” This last is the largest portion of the genital tube, and is dis- 
tinguished by its well-marked power of peristaltic action. The vagina, 
which is distinguished from the uterus by its narrowness and its muscular 
walls, opens at very different points of the body. Generally, as for 
Instance.in Ascaris, Spiroptera, Strongylus, Oxyuris, Cucullanus, and Tri- 
chocephalus, the Vulva, consisting of a transverse fissure, and often sur- 
rounded by a very remarkable fleshy swelling, is situated either a little in 
front of, or near the middle of the body ; but sometimes it opens just in front 
of the anus.© The sperm is usually so accumulated in the bottom of the 
uterus, that this is probably the locality of fecundation,® 
In the males, the posterior portion of this tube is the testicle; another 
portion of it, which is short and constricted, is the Vas deferens, which 
passes into a dilated portion,— the Vesicula seminalis. Usually this last is 
separated by a constriction from the Ductus ejaculatorius, which opens into 
another muscular tube (sheath of the penis). At the anterior portion of 
this last, is a horny, copulatory apparatus. The simple or double penis is 
of variable length, and is protruded by the muscular contractions of its 
sheath through the external opening, which is always situated at the poste- 
2 The formation of eggs in various Nematodes borders of the vulva appear quite swollen, With 
lias been described by Szebold (Burdach’s Phys- 
inl. loc. cit. p. 208), by Bagge (Dissert. de. Stron- 
gylo, &c., fig. 1-5), and Kélliker (Muller's Arch. 
43, p. 69, Taf. VI. fig. 20). I have found a 
rachis in the ovaries of Ascaris aucta, lumbri- 
coides, mystax, osculata, Cucullanus elegans, 
and Strongylus inflecus. ‘The eggs of these, 
while yet immature and flattened, have a point on 
one of their extremities by which they are attached 
to the rachis. 
With. those of Ascaris lumbricoides, this point 
is very long during a certain period of develop- 
ment, and the opposite end has many deep sulca~- 
tions, giving it a remarkable appearance; see 
Henle, in Miller’s Arch. 1835, p. 602, Taf. XIV. 
fig. 1L. 
In the mature eggs, which are nearly always oval, 
it israre that the double colorless envelope can be 
elearly perceived. With T'richosoma, and Tri- 
chocephalus, there is a short diverticulum at each 
extremity of the egg. But in Ascaris dentata, 
there is-at this same place a long fibrillated filament; 
see Mayer, Beitr. Taf. II. fig. 8, and Kélliker, 
in Muller’s Arch. 1843, Taf. VI. fig. 16-19.* 
3 With Ascaris dactyluris, Cucullanus ele- 
gons,, Strongylus nodularis, and striatus, the 
* [§ I17, note 2.) Primitively, the ova of Asca- 
ras consist of nucleolated cells, which are polyhe- 
dral from mutual pressure. These increase in size 
gradually, in their passage down towards the ovi- 
duct, and the granules of the liquid lying between 
the nucleus or germinative vesicle and the cell-wall 
Trichosoma, this swelling is so attached to the 
vulva as to resemble a prolapsus of the vagina 
(Dujardin, Hist. d. Helm. Pl. I.). 
With Filaria attenuata, inflero-caudata, mihi 
(from the pulmonary cysts of Delphinus pho- 
caena), and papillosa (see Leblond, Quelques 
matériaux pour servir a Vhistoire des Filaires et 
des Strongles, 1836, Pl. II. fig. 1), the vulva is at 
the side of the mouth. 
With Strongylus paradoxis, it is swollen to the 
form of a bladder, and is situated near the caudal 
extremity ; while that of Ascaris paucipara is 
directly upon the anus. 
4 See Bagge, loc. cit. p.12; and Kélliker, in 
Miiller’s Arch. 1843, p. 72. 
5 For the male genital tube, see Mayer, Beitr. 
Taf. I., and Cloquet, Anat. &c. Pl. I. fig. 5, Pl. 
Tl. fig. 8. As yet I have observed only a few 
exceptions to this typical form with male Nema- 
todes. : 
With Filaria attenuata, the posterior portion 
of the testicle is bifurcate, and with Ascaris vesi- 
cularis, there are two moderately large caecal pro- 
longations which arise from the Vesicula semi- 
nalis at the place where it empties into the Vas 
deferens. 
become developed into cells, and in this way the 
mature ova are formed. Probably no better op- 
portunity is afforded to perceive that morphologi- 
cally the ovum is at first only a nucleolated or 
nucleated cell; see Letdy, loc. cit. p. 43, Pl. VIL. 
fig. 14, c. — Ep. 
