390 . THE ARACHNOIDAE. $ 316. 
the anterior portion of their body on aquatic plants, and in this position, 
wait the completion of their moulting.“ The secreting organs of this 
substance have not yet been discovered. 
CHAPTER IX. 
ORGANS OF GENERATION. 
§ 316. 
All the Arachnoidae reproduce by a sexual generation, and their male 
and female genital organs are situated upon different individuals. The eggs 
are fecundated in the genital organs of the females, and the males have 
often copulatory org2ns of a very singular character. The Tardigrada form 
an exception in this respect, being hermaphrodites, and wanting the copula- 
tory organs. 
In general, the genital organs of the Arachnoidae are composed of the 
following parts. The ovaries or testicles are always double, but sometimes 
blended together on the median line. They are situated in the abdomen, 
and have two excretory ducts, which usually open at a common genital ori- 
fice at the base of the abdomen, or under the thorax. The ovaries, when 
filled with eggs, have always a botryoidal aspect. Only a few. species 
have an ovipositor or a penis. The excretory ducts of both the ovaries 
and the testicles sometimes have appendages which, with the females, 
serve to receive the sperm, or to secrete a viscous substance for enveloping 
the eggs ; and which, with the males, represent an epididymis or the sem- 
inal vesicles. Quite often, the males differ from the females in a special 
modification of their cheliceres, their palpi, or some of their legs. When 
this is the case, these organs serve, during copulation, to hold the females, 
or play the part of a penis. 
The eggs of the Arachnoidae are spheroidal, rarely oval,” and composed 
of a smooth chorion enclosing a vitellus consisting of vesicles filled with a 
colorless and, also, often highly-colored fat, in the midst of which is con- 
cealed the germinative vesicle. The germinative dot is sometimes simple, 
sometimes composed of a group of small granules.° The eggs of Lycosa, 
Thomisus, Diomedes, Salticus and Tegenaria, are remarkable; for, beside 
the germinative vesicle, they contain, before being filled with the vitellus, 
a peculiar, round, finely-granular, solid nucleus.” 
14 According to Duges (Ann. d. Sc. Nat. I. p. 
140), Hydrachna cruenta, adult, before moulting, 
bores into aquatic plants by means of its oral or- 
gans. But I have seen it fixed, also, upon smooth 
glass walls, with the parts of its mouth enveloped 
in a kind of cement. F 
1 The eggs are oval with the Oribatea and Scor- 
pionidae. 
2 The germinative dot is simple and flattened 
with Scorpio, Thomisus, Theridion, Micry- 
phantes, Lycosa, Phalangium, Obisium, Trom- 
bidium, Hydrachna, Ixodes, Oribates, Bdella, &c. 
It is composed of a group of granules with Epeira, 
Clubiona and Salticus ; see Wagner, Prodom. 
&c. loc. cit, p. 8, Tab. I. fig. 11 (Epeira). 
8 This nucleus which appears to contain a cen- 
tral nucleolus, is distinguished, with direct light, 
by its dirty-yellow color, and it has always ap- 
peared tome that there were detached successive- 
ly from its surface several layers of granules 
which mixed with the albumen, without the nucle- 
us diminishing in size. At all events, this nucleus 
plays an important part in the development of the 
eggs, for it appears very early, and does not disap- 
pear until quite late. It has also been observed 
