§ 292. 353 
THE CRUSTACEA. 
shell and the posterior part of the back.” The females of Daphnia have, 
beside those eggs which are rapidly developed in this cavity, another kind 
known as the hibernating eggs, and in which no germinative vesicle is 
observed. They are always found in couples in a thickened, saddle-like por- 
tion of the shell of the animal, which is often of a black color, and separ- 
ated from the shell by a kind of moulting. Thus enveloped in a bivalved 
capsule, they are protected against the severities of the winter. 
Among the Phyllopoda, the Apodidae are distinguished for the very large, 
multiramose, ovarian follicles which border the two oviducts on every side ; 
these last are straight and large, and situated on the side of the digestive 
canal. With Apus, each of them sends off, at about its middle, a short, 
excretory canal, to the eleventh pair of feet, in which there are two alveo- 
late receptacles with covers for the reception of the eggs.” With the 
Branchiopoda, the ovaries consist of two straight coeca, situated in the 
tail, on each side of the intestine. Their upper extremity, beneath the last. 
pair of feet, passes into an elongated receptacle. These two receptacles, 
separated from each other only by a thin partition, have a narrow outlet at. 
their posterior extremity, and form, under the base of the tail, a kind of 
oblong tumor, into which the hard and granular eggs are constantly cast 
from the contractions of special muscular bands. There are, moreover, 
on the sides of the body above the last pair of feet, two oblique horny 
plates, which the males, during copulation, seize with their cephalic pincers. 
With the Poecilopoda, the cephalothorax contains two ramified ovaries, 
3 See Straus, Mém. sur les Daphnia, loc. cit. p. 
418, Pl. XXIX. and Jurine, Hist. d. Monocl. Pl. 
VUL-XVI. The genera Argulus and Cypris dif- 
fer, moreover, from the other Entomostraca, in 
that they do not bear about their eggs after laying, 
but deposit them on foreign bodies; see Jurine, 
Meém, sur PArgule, loc. cit. p. 451, and Straus, 
Mém. sur les Cypris, loc. cit. p. 54. 
Tab. I. (Apus). With Limnadia, and Isaura, a 
special receptacle is wanting ; the eggs are attached 
to the feet probably by the aid of their hairy 
external envelope ; see Brongniart, loc. cit. p. 88 5 
Straus, Mus. Senckenb. loc. cit. Taf. VII. fig. 16, 
and Joly, loc. cit. p. 308, Pl. IX. A.t 
6 See Prevost, in Jurine’s Hist. d. Monocles, p. 
228, Pl. XX. fig. 1, 10 (Chirocephalus). This au- 
4 The formation of the saddle, which is i 
ly d with the deposition of the hibernating 
eggs, has been called by Jurine the Maladie de la 
selle. But it has been before observed by Muller 
‘Entomostr. p. 84, Tab. XI. fig. 9-11, Tab. XII. 
g- 5), and by Ramdohr (loc. cit. p. 28). See, also, 
Straus, loc. cit. p. 415, Pl. XXIX. tig. 16, 17, and 
Jurine, Hist. d. Monocl. p. 120, Pl. XI. fig. 1, 4.* 
5 See Schaeffer, Der krebsartige Kiefenfuss, p. 
79, Taf. LY. fig. 2-7, and Zaddach, loc. cit. p. 51, 
* [§ 292, note 4.] Recent investigations upon the 
y and development of the Crust indi- 
cate that the pk ab tioned, of the 
thor err ly declares, moreover (loc. cit. p- 
207), that the females of this animal have, also, at 
the end of the tail, openings into which the sperm is 
received during coition. See also Joly (loc. cit. p. 
240, Pl. VII. fig. 12, Pl. VIII. fig. 4), who regards 
the receptacles of the eggs, with Artemia, as the 
ovaries. The eggs with a solid, granular shell, of 
Branchipus, have been pretty distinctly figured by 
Schaeffer (Der fischform. Kieferifuss, fig. 14). 
subject, see Lidvin, Die Branchiopoden der Dan- 
ziger Gegend, 1848, p. 11. et seq.; Baird, Brit. 
reproduction by means of a second kind of eggs 
(so-called), is far from being limited toa few of 
these animals. Indeed, it is probable that all or 
most of the Entomostraca reproduce by this mode. 
As mentioned on a preceding page, these phenome- 
na do not appear to me to belong to true oviparous 
reproduction, but must be considered as a kind of 
internal gemmiparity. The so-called winter-eggs 
are, therefore, not eggs, but buds (gemmae)—a 
view which is borne out by their composition, ~ 
gthere being no germinative vesicle and dot. This 
subject will be discussed with some detail below (note 
under §355) when speaking of the Aphides—animals 
with which I have traced these phenomena with 
some care. For many interesting details on this 
30* 
Ent tr. &c. loc. cit. passim ; Zenker, Physiol- 
ogische Bemerkungen tiber die Daphnoidae, in 
Mhuiller’s Arch. 1851, p. 112 ; Leydig, Ueber Ar- 
temia salina und Branchipus stagnalis, in Siebold 
and Kélliker’s Zeitsch. III. 1851, p. 297. — Ep. 
t [ § 292, note 5.) For the female genital organa 
of Artemia and Branchipus, see Leydig (loc. cit. 
Siebold and Kélliier’s Zeitsch. III. p. 300). Jo- 
ly, it would appear, did not observe the ovaries of 
Artemia, but has described the egg-capsules as 
such. The real ovaries here consist of sacs or 
pouches, lying near the dorsal surface of the abdo-~ 
men, and extending to the second abdominal ring 5 
these ovarian sacs pass into a vesiculiform dilata- 
tion, which has non-muscular walls, and corre 
sponds to a uterus. — Ep. 
