$ 164. THE ANNELIDES. 177 
ving is usually. whitish or yellowish, but rarely of a more marked 
color. 
With the Hirudinei and Lumbricini, the spermatic particles are filamen- 
toid and very active, while with the other Annelides they have the form of 
Cercariae. 
§ 164. 
With the Hirudinei, and Lumbricini, the two sexes are always united in 
the same individual. The sexual organs consist of testicles, vasa deferen- 
tia, and vesiculae seminales; then, ovaries, oviducts, and the male and 
female copulatory organs. The female copulatory organs are upon the 
ventral surface of the anterior part of the body and behind the male 
organs— so that two individuals by placing together their anterior ventral 
surfaces in an inverse position, can be mutually impregnated.” 
The excretory ducts of both sexes are often lined with a very delicate 
ciliated epithelium. 
from the eggs of’ other Annelides, in containing be- 
tween the vitellus and vitelline membrane a layer 
of caudate cells. These cells, of variable number 
and size, but always’ of uniform size in the same 
egg, have often been compared, from their form, to 
Naviculacae ; see Henle, in Miller’s Arch.. 1835, 
p. 591, note, and Hy are De vermibus qui- 
busdam, &c., Tab. II. fig. 11 
8 The vitellus is rose-colored, or greenish, with 
Clepsine, and violet with Polynoe. 
4 The development of the spermatic particles of 
the Hirudinei and Lumbricini is very remarkable. 
The cell-membrane of the parent cells, in which the 
spermatic particles are usually developed, disap- 
pears before these last are developed. There arethen 
small cells grouped around a discoid nucleus. These 
cells lengthen out, and finally become spermatic 
particles, and they remain attached to the disc until 
fully developed. If a bundle of these is placed 
in water, they separate and become intertwisted:in: 
the usual manner ; see Henle, in Muller’s Arch. 
1835, p. 584, Taf. XIV. fig. 4, 6, 7,95 Kddliker, 
Beitr. zur Kenntn. d. Geschlechtsverh@ltnisse, p. 
14, Taf. IL. fig. 16, 18,19; Hi Meckel, Muller's 
Arch, 1844, p. 477, Taf. XIII. fig. 2-10 (Sangui- 
suga, Pontobdella, and Branchiobdella); and 
Hoffmeister, De vermibus quibusdam, »&c., Tab. 
IL. fig. 6-10. From Stannius’ description and fig- 
ures of the sperm of Arenicola (Multer’s Arch. 
1840, p. 375, Taf. XI. fig. 3-6); and Rathkeé of that 
of Amphitrite auricoma (Danzig. Schrift. loc. cit. 
p. 67, Taf. V. fig. 13); and Quatrefages, of that 
of Nemertes mandilia (Régne anim. illustr. Zooph. 
Pl. XXXIV. fig. 3-5), we can conclude that the 
spermatic particles of the other Annelides are de- 
* [ § 163, note 4.] For the spermatic particles 
of the Hermella, see Quatrefages (Ann. 4. Sec. 
Nat. X. 1848, p. 167) ; he describes them as being of 
a cercaria-form. My own results on the spermatic 
particles of the Annelides and their development,: 
do not agree with the view above expressed. Here, 
as elsewhere, I have found them to be the metamor- 
phosed nucleus of the daughter-cells. It is true 
‘ that with the Lumbricini they present some pecu- 
liarities, but these are apparent only. The mul- 
berry-like mass to which they are here found ad- 
herent, is composed of the remains of the develop- 
ment, and the spermatic particles which seem to ra- 
diate from it in all directions present this appear- 
veloped like those of the Hirudinei and Lumbricini. 
While in the excretory ducts of the sperm, the 
spermatic particles are found in bundles ; and when, 
as at the procreative period, many of these bundles. 
are collected together, their very active, undula- 
tory movements give a most wonderful appearance 
beneath the microscope ; see Morren, loc. cit. p. 
178, Tab. XXIV.-XXVIII., and myself in Mudler’s 
Arch. 1836, p. 42. Among the filamentoid sperm- 
atic particles of Hirudinei, those of Branchiob- 
della are worthy of special mention. One of their 
extremities is delicate and spirally turned (see my 
observations, Miller’s Arch. 1836, p. 42, Taf. II. 
fig. 8), and terminates, according to Kélliker, by a 
small vesicle (loc. cit. p. 18, Taf. IL. fig. 16, f.). 
With the Branchiati, the cercarian-form predomi- 
nates, according to Quatrefages (Comp. Rend. 
XVII. 1843, p.-424). With the Nemertini, they are 
either simply filamentoid (Votospermus, accord- 
ing to Orsted, Entwurf. einer Kinth. d. Plattwiirm. 
loc. cit. Taf. III. fig. 54) or more cercarian-form 
(Nemertes, according to Quatrefages, Reéegne 
anim. illustr. Zooph. Pl. XXXIV. fig. 6; and Kél- 
liker, VerhandL d. schweiz. naturf. Gesellsch. bei 
ihrer Versammlung zu Chur. 1844, p. 91). 
For the spermatic particles of the Annelides, see 
especially Kéliiker in the Neue schweiz. Denkschr. 
VUI. p. 33.* 
' See Bojanus, Isis, 1818, Taf. XXVI. fig. 1; 
Brandt, Med. Zool. IL. Taf. XXX. fig. 25 (Sangui- 
suga medicinalis); Leo, Miiller’s Arch. 1835, 
Taf. XI. fig. 3 (Piscicola geometra) ; Morren, 
loc. cit. Tab. XXVII.-XXXI.; and Hoffmeister, 
De vermibus quibusdam, &c., Tab. I. fig. 29, 30: 
(Lumbricus and Enchytraeus).t 
ance because they are then just escaping from the 
daughter-cells, and the more or less adherence of 
the membrane of these last to the particles, gives 
the appearances above mentioned in the note. I 
have observed the same appearances with some of 
the Coleopterous insects, where the development 
occurs unmistakably in special cells. These par- 
ticles are, according to my own observation, hair- 
like with the Hirudinei, and Lumbricini, but are 
pin-shaped with some of the Capitibranchiati>—Ep. 
+ [ § 164, note 1.] See also Leydig, Siebol dand 
Kélliker’s Zeitsch. 111. Hft. 3, p. 318, and Quatre- 
Jages, Ann. d. Sc. Nat. XVIII. 1852, p. 298 
(Branchellion).—Eb. 
