Til den indvendige Flade af Bindevævet er Muskel- 
laget fæstet. Det dannes af Tver- og Længdemuskler. 
Tvermusklerne, Tab. III, Fig. 26, a, a, ere temmelig 
smale, men sammenbundne ved et hyalint, kalkfrit Binde- 
vey til en sammenhængende Hud. De gaa fra den ene 
Længdemuskel til den anden, stundom gaa de henimod 
Midten af Længdemuskelen, hvor de då ophøre, aldrig gaa 
de over Radialnerven eller Radialkarret. De kunne føl- 
gelig ikke faa Benævnelsen Ringmuskler, da de ikke gaa 
fortløbende rundt Legemet; men kunne langt bedre be- 
nævnes 'Tvermuskler, da de udfylde 5 Felter, der frem- 
komme ved Længdemusklernes Anordning. Enhver saadan 
Tvyermuskel bestaar af en Mengde Muskelfibriller, sam- 
menbundne med Bindevæv. 
Længdemusklerne ere 5, Tab. III, Fig. 26, e. En- 
hver Muskel har en Bredde af 1,4””, er fæstet til Huden 
ved en Mængde temmelig stærke Bindeveystraade, og ind- 
tager Dyrets hele Længde. De aftage noget i Bredde, 
saavel mod den forreste som bagerste Ende. Fortil fæste 
de sig paa Mundskivens yderste Rand, just ved Grunden 
af en Tentakel, sende Fibre hen til den indre Del af Mund- 
skiven lige til Mundranden. Der, hvor Længdemusklerne 
fæste sig paa Skiveranden, fremkommer, idet Fibrene vige 
fra hverandre, et spidsvinklet Rum, der opfyldes af Radial- 
nerven og Karret. Bagtil fæste de sig -paa Kloaken rundt 
om dennes Aabning. 
Længdemusklernes Fibriller ere forgrenede og ana- 
stomosere med hverandre. Hele Muskellaget er beklædt 
af et flimrende Peritoneum, der foruden Epithelet bestaar 
af et tyndt gjennemsigtigt Bindevæv, hvori sees enkelte 
Muskelfibre. 
I det tidligere beskrevne hyaline Bindeveey findes lejret 
Kalklegemer af forskjellig Størrelse og Form og i forskjellig 
Mængde. Disse Kalklegemer ligge noget under Kpithellaget 
og rage ikke op i dette. De fremtræde under 3 Former, 
nemlig som Spikler, som Rosetter og som Net. 
å 
Spiklerne findes overalt; men i størst Mængde paa 
Ryggen. De vise sig fornemmelig i to Størrelser, hvorfor 
vi ville benævne dem de smaa og, de: store Spikler. 
De smaa Spikler ere mere eller mindre krumbøjede, kun 
enkeltvis ganske lige, have en Knude paa Midten, imedens 
Enderne ere tildels afstumpede og finttakkede, Fig. WIE, @e 
De ligne meget de Spikler, som findes i Irpas Hud, kun 
ere de meget nmøindre, 0,024”” lange og 0,002”m tykke. 
Disse smaa Spikler ligge dels spredte enkeltvis, saasom 
paa Bugfladen, dels ere de sammenpakkede i Hobe. Fig. 
11, Fig. 10, Fig. 22, dels indtage de et eller flere Lag. 
To the inner surface of the connective tissue is attach- 
ed the muscular layer, composed of transverse and longi- 
tudinal muscles. ; 
The transverse muscles, PI. III, fig. 26, a, a, are 
somewhat slender, but form a continuous muscular mem- 
brane, being webbed together by a layer of hyaline connec- 
tive tissue, without a trace of calcareous deposit. They 
extend from one longitudinal muscle to. the other, reaching 
sometimes almost to the middle of those muscles, where 
they terminate, never crossing the radial nerve or the radial 
vessél. Hence, the appellation of ring, or annular, muscles 
is incorrect, since they do not encircle the body; transverse 
muscles would be a more appropriate term, occupying as 
they do the 5 segments into which, by the arrangement of 
the longitudinal muscles, the surface of the body is divided. * 
Each of these transverse muscles consists of numerous mus- 
cular’ fibrils, webbed together by connective tissue. Å 
The longitudinal muscles are 5 in number, Pl. III, 
fig. 26,e. Hach muscle has a breadth of 1.4”, is attached 
to the integument by a multitude of comparatively strong 
filaments of connective tissue, and protends throughout the 
entire length of the animal. At both extremities they ex- 
perience a slight diminution in length. Anteriorly, they are 
affixed to the extreme margin of the oral disk, each at the 
base of a tentacle, and send off fibres to the inner portion of | 
the disk, or rather to the edge of the oral orifice. These 
fibres abruptly diverging, an acute-angled space, occupied 
by the radial nerve and vessel, is marked off where the 
longitudinal muscles issue from the margin of the oral disk. 
Posteriorly, they are attached to the edge of the anal 
opening. 
The fibrils of the longitudinal muscles are ramous, 
anastomosing one with the other. Over the whole of the 
muscular layer extends a ciliated peritoneum; which, in 
common with the epithelium, consists of thin, translucent 
connective tissue, in which may be discerned a few muscular 
fibrils. | 
In the hyaline connective tissue, deseribed above, are 
calcareous corpuscles, varying alike in form, magnitude, and 
number. These calcareous corpuscles lie a little beneath 
the epithelial layer, none extending up into that division 
of the integument. They are triform, viz. spicular, flos- 
culous, and reticulate. - di 
The spiculæ are everywhere met with, but in greatest 
numbers on the back. The majority are of two magni- 
. tudes, and hence may be conveniently designated the small 
and the large spiculæ. 
The small spiculæ are more or less inflexed, — but very 
few, and those isolated, occur strictly rectilinear, — bearing 
each a protuberance in the middle, and with obtuse or minutely 
serrated extremities, fig. 11 a. They closely resemble the 
spicules. studding the integument in the genus Jrpa, 
but are very much smaller, measuring only 0.024” in 
length and 0.002”” in thickness. A threefold arrangement 
characterises these diminutive spiculæ, some occurring isolated, 
