$166. THE ANNELIDES. 179 
tral surface. The posterior opening connects with a short muscular canal 
which may be regarded as a reservoir of eggs. 
_ From the base of this reservoir, a narrow spiral canal passes off, and 
bifurcating into two oviducts, terminates with two round ovaries, 
From the anterior opening, a long filiform penis may be protruded, 
which, when not erected, lies spirally concealed in a bulbous muscular 
sheath. A Ductus ejaculatorius extending from the seminal vesicles, opens 
into each side of this sheath. These seminal vesicles are formed each by a kind 
of continuation of the vas deferens into a varicose tortuous canal, which lies 
in the midst of a dense cellular tissue. The Vasa deferentia are narrow, 
and passing backwards along the sides of the body, receive upon their 
internal surface the short excretory ducts of the five, nine, or twelve pairs 
of ae isolated testicles, which form a double row near the ventral 
cord. 
With many Hirudinei, a portion of the skin is connected with the sexual 
function. Such is the case with Nephelis, with which numerous cutaneous 
glands are developed upon the back and belly near the female genital 
opening. The skin soon has a bloated, transparent appearance, so that the 
animal appears to have a girdle about its anterior extremity. Before the 
deposition of the eggs, these glands secrete a substance which hardens in 
water, and surrounds the body of the animal like a horny belt. This belt 
is filled with a greater or less quantity of eggs; the animal then withdraws, 
or slips out from’ it, while its two extremities are closed up by its own 
elasticity ; but the embryos developed in this egg-capsule are not thereby 
prevented from making their escape. — 
The Sanguisugae form cocoons in a similar manner; but they are sur- 
rounded with a very thick, spongy substance.” The various species of 
Clepsine form sac-like capsules for their eggs, and which they usually carry 
about with them, attached under their belly, —shielding them with their 
body at the approach of danger. 
five pairs of these organs ; with Haemopis, eight ; 
and with Aulacostomum, twelve (Moquin-Tan- 
don, Monogr. loc. cit. Pl. III. fig. 8; Pl. I. fig. 3, 
1 See Brandt, Mediz. Zool. IT. p. 252, Taf. XXTX. 
A. fig. 45, 465; Moquin-Tandon, Monogr. loc. 
cit. p. 80, Pl. I.-III.; Leo, Miiller’s Arch. 1835, 
p. 424, Taf, XI. fig. 10 (Sanguisuga, Aulacosto- 
mum, Nephelis, Pontobdella, and Piscicola. 
According to the careful researches of Filippi 
qLettera sopra l’anat. e lo sviluppo delle Clepsine, 
p. 16, Tav. I. fig. 5), Grube (Untersuch. tib. d. Ent- 
wickl. d. Clepginen. p. 6, Taf. IIT. fig. 3), and Fr. 
Miller (Miller's Arch. 1846, p. 138, Taf. VIII.), 
the two ovaries of Clepsine and Nephelis, consist 
of long flexuous cords surrounded by two more or 
dess long muscular sheaths, which are uninterrupt- 
edly continuous into the oviducts ; they receive the 
‘eggs as they are detached from the ovaries, and pass 
them along by peristaltic movements. 
2 Sanguisuga has nine pairs of testicles (Brandt 
Med. Zool. II. p. 252, Taf. XXIX. A. fig. 32-44). 
The Vasa deferentia of the seven pairs with Pis- 
cicola are dilated before reaching the two seminal 
vesicles into two long and very flexuous tubes (Epi- 
didymis, according to Leo, loc. cit. 1835, p. 423, 
‘Taf. XI. fig. 10). With Pontobdella, there are 
* [§ 166, note 2.] For many valuable details on 
the genitalia of the Hirudinei, see the often-quoted 
and valuable works of Leydig, loc. cit. p. 120. It 
ins histol 1, as well as ] results. 
ding to him, Pi. /a has six, and not seven 
(£0) pairs of testicles. — Ep. 
A 
Pl. IL. fig. 10). With Nephelis, the arrangement 
is different, there being on each side of the poste- 
rior part of the body, numerous testicular vesicles 
united in a botryoidal manner ; see Moquin-Tan- 
don, Monogr. loc. cit. Pl. III. fig. 4.* 
8 See Rayer, Ann. d. Sc. Nat. IV. 1824, Pl. X. 
fig. 1-6, and Moquin-Tandon, loc. cit. Pl. VI. fig. 
4,e-h. These cocoons are often found as brown 
scales, glued to aquatic plants. Piscicol/a forms 
similar cocoons, but they never have more than one 
egg each ; see Leg, loc. cit. p. 425, Taf. XI. fig. 6 ; 
ee Brightwell, Ann. of Nat. Hist. IX. 1842, p. 
11 
4 See Rayer, loc. cit. Pl. X. fig. 10, and Moguin- 
Tandon, loc. cit. Pl. V. According to Wedeke 
(Froriep’s neue Not. No. 452, 1842, p. 183), the 
medicinal leech ejects from the mouth as a scum, 
the spongy envelope of these cocoons. 
5 See Grube, Untersuch. tiber die Entwick. @ 
Clepsinen, 1844, p. 1. 
t (8 166, note 3.) See, for an histological exami- 
nation of these genital glands in Piscicola, Ley- 
dig, loc. cit. p. 122, Taf. IX. fig. 43, e. 49, a.b. c. 
— Eb. 
