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51
til en stærk Sphincter. Strax ovenfor denne Rand udgaa
de 8 Gastralfilainenter som en bred, med Fryndser
forsynet Krave. Fig. 45, c. 47, d, men skille sig snart i de 8
krusede Organer, der følge langs Septula, Fig. 45, cl. 47. e.
saagodtsom lige ned til Bunden af Mavehulheden, Fig. 47, c.
Af disse Gastralfilainenter er der to, de dorsale, der ere
nogle Millimeter hengere end de øvrige; men det er ogsaa
det Hele, forresten ere de omtrent lige lange.
Gastral-filamenterne ere meget brede efter deres hele Længtle, Fig.
49, c; de dannes af en tynd Bindevævsmembran, beklædt
med de tidligere beskrevne Endothelcellor, der giver hele
Gastralhulheden sit Overtræk. Paa Gastralfilamcnteriie
udvikle Generationsorganerne sig, et Forhold, der i
væsentlig Grad afviger fra, hvad der hidtil er kjendt hos
Pcn-natuliclerne, hvor Kjonsorganerne udvikle sig paa Septula.
I de brede, flotterende Gastralfilainenter udvikles en
stor Mængde runde Kapsler, der allerede meget tidligt
indeslutte Kjonsproduktet, Fig. 52. Disse Kapsler, som ere
stilkede, ere kun lidet forskjellig i deres Bygning hos de
forskjellige Kjøn; de dannes af en fast, hyalin
Bindevævs-membran, der udvendigt er beklædt med Gastralhulhedens
Epithelialovertræk. — og paa hvis indvendige Flade er et
Epitliellag, der hos Hannen (Testikelen) bestaar af
elliptiske Celler, der ere 0,006""" brede paa Midten og 0,013"""
lange med en lidt excentrisk Kjerne, som er næsten rund.
0.001"» bred. og et finkornet Protoplasmaindhold, hvori
sees enkelte, stærkt røde Pigmentkorn, Fig. 53. Hos
Hunnen bestaar Kapselens (Æggestokkens) indre Epitliellag af
runde, temmelig klare Celler, noget lig Endothelcellerne,
men uden ile omtalte Pigmentkorn. I enhver Kapsel hos
Hunnen udvikler der sig kun et Æg, Fig. 52. b, ligesom
Embryodaimelsen foregaar i denne Kapsel, der saaledes
fungerer ogsaa, som l’terus. Vi saa Embryoner liggende i
Kapslerne, og frit i Gastralhulheden fandtes enkelte, der
vare frigjorte, ligesom tomme Kapsler ikke vare sjeldne.
Et saadant Embryo var næsten kugleformet og havde paa
den ene Ende en Indsænkrting, det begyndende
Gastræa-stadium, Fig. 54, a. Umbelhda encrinus føder altsaa levende
Unger. Kjønskapslerne (Testiklerne) hos Hannen vare i
deres fulde Udvikling ganske fyldte med Spermatozoer,
der havde en Pa>reform, Fig. 55. Hovedet var rundt
med en dunkel Flæk i Midten, 0,003""" bredt. Halen var
bred, idet den udgaar fra Hovedet, og temmelig kort;
Spermatozoens hele Længde udgjorde 0,014""". De fleste
Spermatozoer havde tabt deres Hale, saa man iagttog kun
en Mylder af runde, glindsende Legemer, hvori den dunkle
Flæk saaes.
Kjonsorganerne udvikle sig, som tidligere berørt, i
Gastralfilamenterne, hvor de danne store, frit hængende
Drueklaser, Fig. 45. c. 47, /. 49, d, der strække sig saa
muscles converge, forming a strong sphincter. Immediately
above this margin, 8 gastral filaments issue, having the
appearance of a broad fringed collar (fig. 45, c, 47. ei), but
separating themselves, quickly, into the 8 curly organs which stretch
along the septula (fig. 45. ei, 47. e). almost down to the
bottom of the ventral cavity (fig. 47, c). Of these gastral
filaments, there are two; the dorsal ones; which are a few
millimetres longer than the others, but that is all, as,
otherwise, they are about uniform in length. The gastral
filaments are very broad throughout their whole length
(fig. 49. c). They are formed of a thin connective-tissue
membrane, clad with the previously described cells of the
endothelium, which furnish the coating of the whole gastral
cavity. The generative organs develope themselves on the
gastral filaments, a circumstance, that in a material degree
differs from what has previously been known relative to
Pennatulidæ, where the sexual organs are developed on the
septula.
In the broad floating gastral filaments, a multitude
of round capsules are developed, which, already, at an
early stage, enclose the sexual product (fig. 52). These
capsules are pedunculated, and in the different sexes,
are only slightly different in their structure. They are
formed of a firm, hyaloid connective-tissue membrane, which
is, externally, clad with the epithelium covering of the
gastral cavity, and oil whose interior surface, there is an
epithelium layer, which, in the male (the testicle), consists
of elliptic cells, 0,006""" broad at the middle, and 0.013"""
long, containing a somewhat eccentric, nearly round
nucleus, 0,001 broad, and also, a minute granular
protoplasmic contents, in which a few deep-red coloured
granules (fig. 53) are seen. In the female, the inner
epithelium layer of the capsule (the ovary) consists of
round, rather clear, cells, somewhat like the endothelial
cells, but without the coloured granules spoken of. In
each capsule in the female, only one ovum is developed
(fig. 52. b), whilst, also, the formation of the embryo
proceeds in this capsule, which thus, performs as well, the
function of a uterus. We observed embryos lying in the
capsules; and also, in the gastral cavity there were a few
which were detached, whilst, also, empty capsules were not
infrequently seen. Such an embryo was, nearly, spherical in
form, and on the one extremity, had a depression forming
the commencing stage of the gastræa (fig. 54, fl). Umbelhda
encrinas, therefore, gives birth to living young. The sexual
capsules (testicles) in the male, were, in their full
developc-meut, quite filled with spermatozoa. These were pyrifoiili
(fig. 55) with round heads, having an indistinct spot
in the middle, 0,003""" broad. The tail was broad as it
issued from the head, but rather short. The entire
length of the spermatozoa measured 0,014""". Most of
the spermatozoa had lost their tails, so that, only a throng
of round, bright corpuscles was observable, in which the
indistinct spots were seen.
The sexual organs develope themselves, as previously
stated, in the gastral filaments, where, they form, large,
freely pendant, grape-like clusters (fig. 45, e, 47. /. 49, d),
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