Det indre Skelet. 
Kalkringen er temmelig rudimentær, ligner vistnok 
“meget Kalkringen hos Elpidia og Irpa; men er baade langt 
smekkrere og ikke saa inderlig sammenbunden, som hos 
disse. Den dannes af 5 Stykker, Tab. III, fig. 27, dey 
nærmest maa svare til Radialstykkerne hos: andre Holo- 
thurider. Ethvert Stykke, der er omtr. 1,5” langt, har 
et nesten firkantet Midtparti, Fig. 28, a, som er 0,068”” 
bredt og- ikke fuldt saa hojt. 
delt i to Dele, en forreste, der ér smalest. og en bagerste. 
Fra den forreste Del udgaa 6 Stave, hvoraf de to hæve 
sig skraa fortil og opad imod Spiserøret, og ende svagt 
kølleformigt, Fig. 28, b, b; 
et Stykke ovenfor Udspringet i. to Grene, Fig. 28, cc, 
hæve sig bagtil og opad, og synes at følge Tentakelkarrene. 
Fra Midtpartiets bagerste Del udgaa paa hver Side 4 lange 
Stave; Fig. 28, d, d, d, d, der 
derne, og hvoraf den længste løber noget paaskraa henimod 
Enden af den tilsvarende Stav paa det nærmest tilgrænd- 
sende Kalkstykke, Fig. 27, a,a. Enderne af disse Stave ere 
bladformige, og forsynede med Indsnit og Huller, Fig. 28. De 
her nævnte Kalkstave fra Midtpartiets bagerste Del ere 
smalere ved deres. Udspring; paa Midten ere de 0,013” 
tykke, og Enderne ere indtil 0,040”” brede. . De saaledes 
beskrevne 5 Kalkstykker ere yderst fine, og kunne vanske- 
ligen opdages med det blotte Øje. Naar de ere i Situs, 
danne de en femkantet Ring, idet de bagerste, fornemmelig 
de længste Stave, naa saa langt til hverandre, at Ringen 
derved afsluttes. Kalkstayene ligge ‘ikke paa hinanden, 
saaledes som Tilfældet er hos Elpidia og Irpa; 
Ender ere bundne sammen med Bindevæv, 
Kalkringen ligger fæstet i den Bindevævshud, ‘der danner 
Svælgsinus: Kalkringen ligger en god Del foran Vandkar- 
ringen; og Midtpartiet af ethvert af dens Stykker findes 
just der, hvor 'de-5 Hovedstammer dele sig for at afgive 
Grene til Tentaklerne, Tab. I, fig. 9; a, 
gens Stave fæster sig dels Muskelbeand,. dels Bindevæys- 
traade, der udgaa fra Svælget og fra Mundskiven. Til 
nogen synderlig Støtte for Noget kan visselig ikke Kalk- 
ringen tjene, da den er saa yderst fint bygget. 
men deres 
ligesom hele 
Vandkarsystemet. 
Ringkanalen. er dækket af den Bindevævsmembran, 
«der danner Svælgsinus. Denne Membran, der er temmelig 
tyk, er fastvoxet til den bagerste Del af Ringkanalens ind- 
Dette Midtparti er ligesom 
de øvrige 4, der hver deler sig * 
ligesom straale ud til Si- - 
Paa Kalkrin- - 
10 
- together. 
sulated Nematoids; we failed, however, to. detect any organic 
disturbance, saving traces of muscular atrophy where the 
Nematoids lay embedded. 
Calcareous Skeleton. 
The calcareous ring is imperfectly developed, indeed 
almost rudimentary; true, it presents considerable resem- 
blance to the ar ring in Elpidia and Irpa, but 
is of far more slender dimensions, and less compactly put 
It consists of '5.calcareous segments, Pl. IIT, fig. 27, 
corresponding to the radial plates in other Holothurians. 
Each of these segments, measuring about 1.5” in length, has. 
an almost quadrate central section, fig. 28. a, 0.0687” 
broad, and not, quite so deep. This central section: is, as 
it were, bipartite, the anterior part being the narrower. - 
Affixed to the anterior part are 6 calcareous rods, two of 
which protend obliquely forwards in the direction of the 
æsophagus, with a slightly claviform extremity, fig. 28, b, b; 
the remaining 4, each of which branches out a little above 
the point of origin, with two ramifications, fig. 28. ¢,c, and 
protends posteriorly upwards, apparently protending along the 
tentacular vessels. To the posterior -part of the central + 
affixed on either side 4 long calcareous rods, 
section are 
fig. 28, d,d,d,d, radiating, as it were, to the sides, the longest 
of which protends somewhat obliquely towards the extremity: 
of the corresponding rod on the calcareous segment next 
adjacent, fig. 27, a,a. - These rods have petaloid extremities, 
furnished with apertures and incisions, fig. 28. The rods: 
springing from the posterior part of the central section, are 
slenderest at their origin; in the middle, they measure 
0.013”" in thickness, having a breadth of 0.040” at the . 
extremities. The 5 calcareous segments described above are 
exceedingly minute; and can with difficulty be discerned with 
the naked eye. When in situ, they present the appearance 
of a pentagonal ring, the posterior rods, and in particular 
the longest of them. approximating sufficiently to close the © 
ring. The calcareous rods do not lie one.above the other, 
as in Elpidia and Irpa, but their extremities are webbed 
together by connective tissue, and the ring itself lies wholly 
embedded in the menibrane of connective tissue forming’ the 
pharyngeal sinus.. The calcareous ring is placed consider- 
ably in advance of the water-vascular ring; and the central 
section of each of its segments is located exactly where the 
5 principal stems ramify to the tentacles, Pl I, fig. 9, a, a.. 
The rods of the calcareous ring are pinnated with muscu- 
lar bands and filaments of connective tissue, proceeding from 
the gullet and from the buccal disk. From the extreme 
fragility of its structure, the calcareous ring can hardly 
be of much importance ‘as a means of strengthening any 
part of the organism. 
Aquiferous System. 
The annular canal is enveloped by the membrane of con- 
nective tissue constituting the pharyngeal sinus. This mem- 
brane, which is rather OMNIA IS connate with the posterior 
