392 THE ARACHNOIDAE. $$ 317, 318. 
I. Hermaphrodite Arachnoidae. 
§ 317. 
The Tardigrada have only a single, but large, ovarian tube, applied on 
the posterior half of the digestive canal and opening into the cloaca. This 
last which is only a dilatation of the rectum, receives, also, two lateral, 
narrower, seminiferous tubes, together with the excretory orifices of a 
pyriform seminal vesicle. With Milnesium, Emydium, and Macrobiotus 
ursellus, the eggs are surrounded by a smooth chorion, and deposited in a 
solid epidermis which is detached during the moulting,— so that all the 
egos are finally contained in this envelope. But the other species of 
Macrobiotus shield their eggs in another manner, by surrounding each 
with a very solid, granular capsule. 
IT. Female Arachnoidae. 
§ 318. 
The female organs of the Acarina consist of two ovarian sacs, the ovi- 
‘ducts of which open in a common vulva situated in the middle of the belly, 
or further forwards on the thorax, sometimes between, sometimes behind 
the last two pairs of legs. With many of these animals, the oviduct 
opens into a protractile ovipositor by the use of which the eggs are lodged 
under the epidermis of plants or animals. 
1 For the genital organs of the Tardigrada, see 
Doyere, loc. cit. p. 350, Pl. XIII. XIV. XVI. 
Goeze (Bonnet, Abhandl. aus d. Insekt. 1773, p. 
374), and O. F. Muller (in Fuessly, Arch. d. In- 
sektenkunde, Hft. VI. p. 27, Taf. XXXVI. fig. 4, 5) 
had already observed that the Tardigrada deposit 
their eggs in their cutaneous envelope.* 
1 With the Gamasea, and Ixodea, the vulva is sit- 
uated on the thorax ; while, with the Trombidina, 
Bdella, Hydrachnea, and Oribatea, it is upon the 
belly ; see Treviranus, Verm. Schrift. Taf. V. 
(Hydrachna and Trombidium) ; Audouin, Ann.d. 
Sc. Nat. XXV. Pl. XIV.; J. Muller, Nov. Act. Nat. 
Cur. XV. Tab. LXVII.; and Treviranus, Zeitsch. 
f. Physiol. lV-Taf. XVI. fig. 2 (Iwvodes). For the 
ovaries and oviducts of the Acarina, we have only 
ahe works of Treviranus,Verm. Schrift. I. p. 47 Taf. 
VL. fig. 32 E. q.(T'rombidium), and Zeitsch. f. Phys- 
Gol. LV. p. 190, Taf. XVI. fig. 7, 8, 10, a. a. Iwodes). 
I have observed with Ixodes ricinus the following 
peculiarities, which were probably overlooked by 
Treviranus with Izodes americanus. The two 
Jong ovaries anastomose arcuately at the posterior 
extremity of the abdomen. The two oviducts, here 
given off, open right and left into a pyriform uterus 
whose veck communicates laterally with a large 
waecum coming from the vulva. This caecum is 
divided by a septum into a posterior, or larger, and 
an anterior, or smaller, portion. The first receives 
the sperm which flows from the second during cop- 
ulation, and thence passes into the uterus and even 
into the oviducts. The anterior portion represents 
the vagina properly speaking, and is in communi- 
*{[ § 317, note 1] See also Kaufmann (oc. 
cit. in Siebold and Kélliker’s Zeitsch. III. 1851, 
p. 220), who has studied the development ¢* the 
A great number of Mites 
cation with two short cylindrical glands filled with 
transparent cells, and which secrete probably 4 
substance for enveloping the eggs. I have, more- , 
over, found with other Acarina (for example, with the 
Hydrachnea, Gamasea, and Oribatea) various or- 
gans belonging to the genital apparatus, but without 
perceiving their relations as clearly as with Irodes. 
However this may be, I am convinced that Dujar- 
din (Ann. d. Sc. Nat. III. p. 20) goes too far in 
saying that, with most Acarina, the eggs are devel- 
oped loosely in the parenchyma of the body, with- 
out the necessity of an ovary with proper walls. 
According to this same naturalist (Ibid.), the Oriba- 
tea are viviparous and have a large vulva which 
can be closed by two lateral alae, and before which 
is an orifice closed also by a similar apparatus, 
This last orifice belongs to a tube which Dujardin 
regards as a penis ; so that the Oribatea would be 
hermaphrodites. As to the first point, — the vivipar- 
ity of these animals, I have verified it for Hoplo- 
phora, Zetes and Oribates ; but I cannot say as 
much of the second point, for, as I have satisfied. 
myself, the posterior orifice is an anus, and the 
anterior a vulva having an ovipositor. 
2 For example, Hydrachna ; see Dugés Ann. d. 
Sc. Nat. I. p. 165. A parasitic mite long known 
under the name of Hydrachna concharum or Lim= 
nochares anodontae, and which lives in the cavity 
of the mantle of Anodontae, buries its eggs deeply 
in the skin of that organ; see Pfeiffer, Naturg. 
deutsch. Land u. Stisswasser-Mollusk. Abth. II. 
p- 27, Taf. I.; and Baer, Nov. Act. Nat. Cur. XIIL. 
p. 590, Tab, XXIX. 
eggs from their first stages, in the ovary of Macro- 
Vius Dujardin. — Ep. 
