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22
Indenfor Læderhuden ere de to Muskellag, nemlig
Tvermusklerne og Længdemusklerne. Tvermusklerne, der
ere bundne til den indre Flade af Corium, danne næsten
en sammenhængende Hud, kun skilte fra hverandre ved en
yderst fin Bindevævsstribe, hvori findes smaa Kalkkorn.
Henimod Dyrets bagerste Ende blive Tvermusklerne noget
stærkere og danne her en Sphincter omkring Analaabningen.
I den forreste Ende hjælpe de til at danne Sphincteren om
Munden. Hvorvidt disse Tvermuskler gaa uafbrudt rundt
Legemets indre Hudflade og saaledes danne virkelige
Ringmuskler, eller de ere afbrudte ved Længdemusklerne, skulle
vi ikke med Sikkerhed kunne afgjøre, da vi ikke have havt
Materiale nok til en saadan Undersøgelse, der forøvrigt
frembyder adskillige Vanskeligheder; men efter hvad vi
have seet, tro vi helst, at de virkelig ere afbrudte i
Lighed med, hvad vi anførte ved at omtale Tvermusklerne hos
Trochostoma
Længdemusklerne ere 5. hvoraf 2 paa Ryg- og 3 paa
Bugfladen. De strække sig fra Munden til Analaabningen,
ere enkelte, temmelig tykke, omtrent 0.8"" brede, og
bindes foruden til Corium ogsaa til Tvermusklerne med en
Mængde stærke Bindevævstraade. Fig. 3. a. Paa Dyrets
bagerste Ende blive de noget smalere, og paa den forreste,
hvor de ligeledes smalne af, gaa de over paa Mundskivens
Underflade og fæste sig i Nærheden af Munden.
Muskellaget er beklædt med Bughinden (Peritoneum), der dannes
af Bindevæv, hvori findes enkelte Muskelfibre, yderst smaa,
spredte, aflange Kalkkorn, og paa hvis indre Flade er et
flimrende Epithelovertræk.
I Kroppens Hud findes Kalklegemer, der optræde
under to Hovedformer, nemlig som Stave (Spilder) og som
elliptiske Skiver. Spiklerne ere temmelig spredte og kun
paa enkelte Steder, saasom henimod Fødderne, mere
samlede. De ere meget smaa, fra 0.054—0.080™" lange, og
fra 0.002—0.003"" brede, have hyppigst en krummet Form,
noget nærmende sig Hesteskoens. Fig. 5, 5, 5, medens
enkelte ere næsten lige, Fig. 4, 6, 6. De have paa Midten
en Knude, og mod begge Ender ere kle tildels forsynede
med fine Takker. Fig. 5. (i, 7, kun yderst sjelden ere de
forgrenede. Fig. 8. Det er især i det ydre Lag af
Læderhuden, at disse Spikler ere leirede. dog hænder det. at
man ogsaa træffer enkelte i det indre Lag.
De elliptiske Kalklegemer findes væsentligst i det
indre Lag; men dog støder man paa dem imellem
Kalk-spiklerne i det ydre Lag. De ere flade, bestaa af en
peri-pherisk Del, som er bredest og ufarvet, og et Centrum, der
1 Magazin for Naturvid. 24 ß., pag. 232. Christiania 1878.
Underneath the corium are the two muscular layers,
consisting of transverse and longitudinal muscles. The
transverse muscles, which are attached to the inner
surface of the corium, constitute an almost continuous
integument, separated as they are by an exceedingly
thin strip of connective tissue, in which occur minute
calcareous granules. In close proximity to the posterior
extremity of the body, the transverse muscles become
somewhat stronger, forming a sphincter round the anal
opening. At the anterior extremity, they contribute in
forming a sphincter round the mouth. Whether these
transverse muscles uninterruptedly encircle the body on the
inner surface of the integument, and thus constitute true
annular muscles, or whether they are intersected by the
longitudinal muscles, we have as yet been unable to determine;
the materials before us were far too scanty for arriving at
a decision on so intricate a subject, the investigation of
which must in itself be attended with very considerable
difficulty; but. judging from the data our observations have
supplied, we are prone to believe there is an intersection,
such as occurs in Trochostoma, to which we called
attention when describing the transverse muscles in that genus.1
The longitudinal muscles are 5 in number — two on
the back and three on the belly. They extend from the
orifice of the mouth to the anal opening, are disconnected,
rather thick, about 8™" broad, and webbed to the
transverse muscles as well as to the corium by numerous
filaments of connective tissue, fig. 3. a. At the posterior
extremity of the body they diminish in thickness, and at the
anterior, where they likewise assume a more slender
appearance. they protend to the under surface of the oral
disk, being connected with it in the vicinity of the mouth.
The muscular layer is covered by the peritoneum,
consisting of connective tissue, in which are a few muscular
fibres, numbers of scattered, exceedingly minute, oblong
calcareous particles, and with a ciliated epithelial tunic on
its inner surface.
In the skin of the body are numbers of calcareous
corpuscles, occurring principally in two forms, — as slender
acuminate rods (spiculæ) and as elliptic plates. The
spic-ulæ are rather scattered, exhibiting at a few points
only, in proximity to the suckers for instance, a closer
arrangement. They are exceedingly minute, from 0.054"" to
0.080"" in length, and from 0.002"" to 0.003"" in breadth,
and the greater part curvate, not unlike a horseshoe, figs.
5, 5, 5. some, however, almost straight, figs. 4. 6, 6. In the
middle of each spicula occurs a small protuberance, and parts
of both extremities are minutely serrated, figs. 5. 6. 7 ; but
very few of these spiculæ branch, figs. 8. It is more especially
the outer layer of the corium through which the spiculæ
are distributed, a few only being met with in the inner.
The elliptic corpuscles occur chiefly in the inner layer;
some however are dispersed among the spiculæ in the outer.
They are flat in appearance, and consist of two parts, one
peripheric and uncoloured. which is the broadest, and one
1 Magazin for Naturvid. 24 Bind, pag. 232. Christiania 1878.
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