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ital organs are situated upon both sides of the body between the branchial 
membrane and the muscular wall with which they are intimately blended. 
They form, sometimes several round or angular projections divided into 
two groups, and sometimes four long crests whose four distinct secretory 
ducts open, after a short course, into the space included between the 
branchial membrane and the muscular sac, at a variable distance from the 
anal tube. 
With the Brachiopoda, ovaries only have as yet been found. These 
surround the liver, and stretch upon both valves of the mantle around the 
minute branches of the branchial vessels. 
With the Lamellibranchia, there are both hermaphrodites and separate 
sexes. But the last are much the more common; for the first have as yet 
been confined to Cyclas,” Pecten,® and Clavagella. The testicles and 
ovaries lie directly behind each other on each side of the body, between 
the liver, intestine, and kidney. Their excretory ducts have not yet been 
satisfactorily made out; all that has been observed, is, that with Cyclas, the 
eggs pass between the lamellae of the base of the external branchiae, and, 
being here developed, produce sac-like swellings.™ 
With those species which are of separate sexes,” the two ovaries or 
testicles are situated usually in the 
mentula). The same arrangement has been ob- 
served by Krohn (Froriep’s neue. Not. No. 356, p. 
49) with the testicle of Phallusia, and by Philippi 
with that of a Rhopalaea (Muller’s Arch. 1843, p. 
48, Taf. IV. fig. 9). ‘ 
5 Carus has distinguished, with acuteness, from 
the ovarian group, as being a testicle, a collection 
of projecting angular glands lying with Cynthia 
microcosmus, upon the internal surface of the 
muscular sac (Meckel’s Arch. II. 1816, p. 577, 
Tab. II. fig. 1, 2, &.— and, Nov. Act. Acad. loc. 
cit. Tab. XXXVII. fig. 1, 2, k. k.). Savigny 
also (loc. cit. p. 92, Pl. VI. fig. 2,3) has seen with 
Cynthia microcosmus, and pantex, two glandu- 
lar groups with their excretory ducts as the sexual 
organs, but without determining that one of these 
was a testicle ; while Cuvier (loc. cit. p. 28, Pl. I. 
fig. 3. d. d.) who has observed the testicular 
group with Cynthia microcosmus, did not know 
what to call it. According to Delle Chiaje (Me-~ 
mor. &c. Tav. XLV. fig. 2, h. h.), the genital or- 
gans of Phallusia phusa consist of numerous gland- 
ular projections united into two groups, and hav- 
ing two distinct excretory ducts. With Cynthia 
canopus, the genital glands lie upon four long 
crests, from the upper extremity of each of which 
passes off an excretory duct towards the anal tube 
(Savigny, Mém. loc. cit. p. 96, Pl. VIII. fig. 11, 
2). With Cynthia papillata, there are two of 
these crests curved in a loop-like manner. (Savig- 
ny, loc. cit. p. 92, Pl. VI. fig. 41, 42, or Delle 
Chiaje, Memor. III. p. 191, Tav. XLVI. fig. 1, 1.1. 
and Descriz. &c. ILI. p. 27, Tav. LXXXII. fig. 11, 
h.h.). From the two extremities of each of these 
passes off an excretory duct; and in comparing 
this arrangement with that of Cynthia canopus, 
it might be inferred that this loop-like disposition is 
due to the fusion of two glandular crests. As to 
which of these crests are ovaries and which testi- 
cles, it would appear from Krohn (Froriep’s neue 
Not. No. 356, p. 50) that all are ovaries, for he has 
observed, with aspecies perhaps identical with 
Cynthia canopus, near the four oviducts, four other 
excretory ducts not easily seen, and which, as Vasa 
Ms ce 
sub-hepatic region of the abdomen. 
danica, I. p. 4, Tab. 5, fig 1, 7) of those of an Or- 
bicula is very beautiful ; while that of Poli is not 
re (loc. cit. II. p. 191, Tab. XXX. fig. 19, 
20). 
7 For the hermaphroditism of this genus see my 
memoir in Miller’s Arch. 1837, p. 383. 
8 According to Milne Edwards (Ann. d. Sc. 
Nat. XVIII. 1842, p. 322, Pl. X. fig. 1), with 
Pecten glaber, the male gland is situated at the 
upper, and the female gland at the lower part of 
the abdomen. The two orifices found at the base 
of the groove of the byssus belong to the testicles. 
With another species of Pecten which I have ex~ 
amined, I was unable to confirm this hermaphro- 
ditism, for I found in the abdomen only either 
testicles or ovaries alone. Moreover the orifices 
just alluded to, appear to meto belong to a gland 
secreting the byssus ; see above § 179, note 4. 
9 With Clavagella, Krohn found the testicles 
beneath the liver, while the ovary surrounded it 
and the stomach (Froriep’s neue Not. No. 356, 
. 52). 
10 These pouches, which, with Cycas, contain 
but a single egg, have been figured by Carus (Erl- 
auterungstafeln, Hft. III. p. 10, Taf. IL. fig. 2b. 3) 
after Jacobson. 
Il Leeuwenhoek (Contin. arcan. natur. detec. 
Lugd. Batav. 1722, Epist. 95, p. 16) had already 
distinguished male and female individuals with 
certain Lamellibranchia, Notwithstanding this, 
he afterwards affirmed that all these Mollusks 
were exclusively females,—an opinion still en- 
tained by some naturalists (see Deshayes, in the 
Cyclop. Anat. I. p. 700, and Garner, in the 
Trans. of the Zool. Soc. II. p. 96), Ihad, however, 
several years before, shown that the sexes were 
separate with Unio, Anodonta, Mytilus, Ticho- 
gonia, Cardium, Tellina, and Mya (Miiller’s 
Arch. 1837, p. 380). The fact has been con- 
firmed by Milne Edwards (Ann. d. Sc. Nat. 
XIII. 1840, p. 375) with Venus, by Owen 
(Lectures, &c., p. 287) with Anomia, and by Kul- 
liker (Beitrage, loc. cit. p. 37) with Pholas. I can 
deferentia, arise from the ramifi 
tubes spread out over the ovaries. 
6 For the ovaries of Terebratula and Orbicula, 
see Owen, loc. cit. The figure of Mudler (Zool. 
ous 
also add to this list, Arca, Pectunculus, and 
Lithod s. I have already mentioned 6 196, 
note 3) how Neuwyler, in taking the ciliary mo- 
tions for those of spermatic particles, regarded the 
kidneys of Anodonta and Unio as the testicles, 
