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31
Blodkar. Hos Hamingia have vi ikke iagttaget noget
saadant Kar, uagtet vi have ved vellykkede Tversnit havt
Anledning til at skjænke dette Punkt vor fulde
Opmærksomhed.
Generationsorganerne.
Vi have tidligere omtalt to Æggebeholdere (Uteri),
der have deres Leie i den forreste Del af Kropshulheden,
Fig. 16, h, h. De ere ægformige, 7mm lange, 4mm brede;
enhver af dem er forsynet med en Udførselskanal, Fig. 16,
i, 17, a, som er rund, 3mra lang, omtrent lmm tyk, og som
gaar ud igjennem de tidligere beskrevne krumbøiede
Papiller paa Bugfladen, i hvis Spids den aabner sig.
Foruden Udførselskanalen har enhver Æggebeholder
en tragtformig Kanal, der ligger over Udførselsgangen,
hvortil den er fastvoxet i en Strækning af omtrent 2mm,
Fig. 16, Jc. 17, b; men bliver fri idet den bøier sig indad
og nedad imod Bugfladen, Fig. 16, I, 17, c, og udvider sig
nu saaledes, at den frie Ende danner Tragtens brede Del,
Fig. 16, m, 17, d. Denne frie Ende, hvis Band er
indskaaren, foldet og besat med Cilier, Fig. 17, e, danner
Indgangen til Kanalen, som fører ind til Æggebeholderens
Hulhed. Hele Tragtens indre Flade, ligesom Kanalen, er
beklædt med et flimrende Epithel. Igjennem Tragten føres
de i Kropshulheden svømmende Æg ind i Æggebeholderne,
der vare fuldproppede af fuldt udviklede Æg, Fig. 16. h,h.
Saavel Udførselskanalen, som Tragten med dens
Ind-førselsgang bestaar af et fast Bindevævslag, hvis indre mod
Lumenet vendende Flade er beklædt med et cilierende
Epithel; men hvis ydre Flade støder til en meget stærk
Muskelhud, der bestaar af Længde- og Ringfibre, hvilke strække
sig udover selve Æggesækkene, der dannes af en temmelig
fast, men næsten vandklar Bindevævsmembran,
gjennem-krydset af Muskelfibre. Saavel Æggesækkene, som de med
dem i Forbindelse staaende Kanaler ere udvendig beklædte
med Peritoneum.
Æggebeholderne ere fæstede til Bugfladen ved enkelte
tynde, temmelig lange Bindevævstraade; forresten hænge de
frit i Kropshulheden.
Æggestokken er fæstet til en Fold af Bugmesenteriet,
Fig. 16, n, ’n, er smal, fladtrykt-baandformig, og strækker
sig fra den yderste Ende af Rectum, hvortil den fæster
sig, til noget foran Midten af Kropshulheden; den følger
Centralnervestrængen, som den næsten ganske skjuler, Fig.
16.
Æggene udvikle sig i Follikelgrupper; saaledes
fandtes i den forreste Del af Æggestokken nogle isolerede
Follikler, Fig. 16, o, o, hvori det begyndende .Æg med
Kim-blære og Kimflæk fandtes, — fuldkommen lig den
Udvik-lingsmaade, der for endel er antydet af Lacaze-Duthiers;
in a blood-vessel. In Hamingia, we failed to detect any
such vessel, notwithstanding we were happy in our
transverse sections of the chord, and took advantage of the
opportunity afforded to give this point our full attention.
Generative Organs.
We have previously had occasion to mention two
ovarian pouches (uteri), placed in the anterior portion of the
perivisceral cavity, fig. 16, h, h. They are ovate in form,
lmm long, 4mm broad, and furnished each with an eferent
duct, fig. 16, i; 11, a, which is round, 3mm long, and about
lmm thick; it passes out through the arcuated papillae on
the ventral surface, previously described, at the point of
which it opens.
Exclusive of this eferent duct, each uterus has a
funnel-shaped canal, protending above the genital duct,
with which it is connate for about 2mn\ figs. 16, k;
17, I, becoming however free as it curves inward and
downward in the direction of the ventral surface, figs. 16,
I; 17, b, and then expanding in such wise, that the free
extremity constitutes the broad part, or mouth, as it were,
of the funnel, figs. 16, m; 17, d. This free extremity
which has the margin folded, incised, and furnished with
cilia, fig. 17, e, constitutes the entrance to the canal
leading to the uterine cavity. The whole inner surface alike
of the funnel-shaped opening a.nd of the canal itself, is
invested with vibratile epithelium; and through this opening
it is, that the egg floating in the perivisceral cavity is
exuded into the uteri, which in the specimen examined
were distended with fully mature ova, fig. 16, h, h.
Both the eferent duct and the funnel-shaped canal,
with its entrance-passage, are built up of a firm-textured
layer of connective tissue, the inner surface of which, facing
the lumen, is clothed with ciliated epithelium; its outer
surface adjoins an exceedingly strong muscular membrane,
composed of longitudinal and annular fibres, protending out
beyond the uterine pouches, the walls of which consist of
comparatively firm-textured, but almost hyaline connective
tissue, intersected by muscular fibres. The uterine pouches,
and the ducts and canals with which they are connected,
have, investing them externally, a peritoneal tunic.
The uteri are webbed to the ventral surface by a
few slender and comparatively long filaments of connective
tissue; for the rest, they depend freely in the perivisceral
cavity.
The ovary, attached to a fold of the ventral
mesentery, fig. 16, n, n, is narrow, depressed, riband-shaped, and
protends from the outer extremity of the rectum, whereto
it is webbed, a little anterior to the middle of the
perivisceral cavity, and accompanies the central nervous chord,
almost entirely concealing it, fig. 16.
The ova develop in follicular groups; in the
anterior part of the ovary were seen, for instance, a few
isolated follicles, fig. 16, o, o, containing rudimentary ova,
with a germinal vesicle and a germinal speck, — their
mode of development being that in part suggested by
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