Full resolution (JPEG) - On this page / på denna sida - Sidor ...
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
Fig. (in, 1, ere Sidevæggene beklædte med transverselle
Muskler, medens i Yei i tr a 1 kammeret. Fig. 60, m,
haveSide-væggene Længdemuskler. I Sidekamrene har den ene Væg
transverselle, den anden longitudinelle Muskler, Fig. (50.
Svælget er langtfra saa foldet, som Tilfældet er hos
Polypen, Fig. 57, c. 60, k; det har imidlertid den samme
histologiske Bygning; kun synes det ydre Epithellag at være
tykkere, Fig. (50, li, og dets Celler at være mindre, Fig. 601, i.
Svælgets øverste Del smalner al’ og gaar over i den lidt
aflange Mund med to tykke Læber, imedens det nedad
Ivar en fri Ende, hvorfra, udgaa to Gastralfilamentor. Fig.
57. (!, som ere temmelig lange og naa lige ned til Bunden
af Zooidens Mavehulhed. Denne forhenger sig i en sinai
Kanal, der gaar over i Coenenehymets Tverkanaler.
Zooiderne tilføre altsaa det indre Kanalsystem i Stokkens
Sarcosoma Sovand, som vistnok maa udgjøre et betydeligt
Kvantum, naar Hensyn tages til Zooidernes overordentlig
store Mængde.
Naar Zooiden er stærkt sammentrukken, danner den
en næsten kuglerund Forhøining, i hvis Midte sees en
liden, rund Aabning eller aflang Spalte, Fig. 5(5, b, og paa
et enkelt af vore Exemplarer ere saagodtsom alle Zooider
paa den Vis sammentrukne; kun ved en skrupuløs
Undersøgelse findes enkelte, der have Tentakelen halvt udstrakt.
Saasnart Tentakelen udstrækkes noget, forlænger Kroppen
sig, Fig. 56, c. og er den fuldt udstrakt, har Zooidekroppen
en ovoid Form, Fig. 5(5, cl. Tentakelen er bevajgelig i
næsten alle Retninger; fra dens Sider udgaa lange,
papillose Pinnuler, der give den et grenet Udseende, Fig. 56, f.
Ikke hos alle findes disse Pinnuler, men naar de findes,
og det er meget hyppigt, have de samme Bygning som
Tentakelen, ere hule, korrespondere med Tentakelens
Hulhed og kunne forkortes og forlænges efter Omstændighederne.
Nogen Aabning paa deres afrundede Ende kunde ikke iagttages.
Figur 56 giver et godt Billede af disse mærkelige Zooider
i deres forskjellige Form, alt eftersom de ere mere eller
mindre udstrakte.
Kalkaxen strækker sig fra Stokkens Bund til dens
overste Ende. Den har sin største Tykkelse paa den
øverste Del af det bulbøse Parti, hvorfra den smalner af
saavel opad som nedad. I sin største Længde er den
firkantet med 4 dybe Furer, af hvilke den paa Ventralfladen
er noget videre end de øvrige, samt 4 afrundede Hjørner,
Fig. (51. Axen bliver i dens øverste og nederste Del alt
mere og mere rund og taber ganske sine Furer, Fig. 62. 63.
I den nederste Halvdel af Bulbus ligger Axen i
Dorsalkanalen, hvor den omtrent 20""" fra Bunden gjør en let
Boining mod Hoire, Fig. 62, hvorpaa den paany bøicr sig
(fig. 60, g). These muscles are covered with similar
epithelium to that, which covers the inner wall of the polyp’s
body. The arrangement of the muscles is, the same as
that previously spoken of as pertaining to the polyp. In
the zooids. there is, also, a symmetrical order, thus: — in
the dorsal chamber (fig. 60, e), the lateral walls are clad
with transversal muscles, whilst, in the ventral chamber
(fig. 60, m), the latöral walls have longitudinal muscles.
In the lateral chambers, the one wall has transversal, and
the other, longitudinal muscles (fig. 60).
The gullet is not nearly so much folded, as is the
case in the polyp (figs. 57, c, 60, /,•); it has, however, the
same histological structure, only, the exterior layer of
epithelium appears to be thicker (fig. (50. It), and the cells
to be smaller (fig. 6(1’, /). The superior part of the gullet
contracts, and [tasses into the somewhat oblong oral
aperture with two labiæ, whilst, it also has, an inferior
free extremity, from which, two gas tral filaments issue
(fig. 97, e); these are rather long, and reach right down
to the bottom of the zooid’s ventral cavity. This is
prolonged into a. narrow canal, which passes over into
the transverse canals of the sarcosoma. The zooids,
consequently, introduce water into the inner ductiferous
system of the sarcosoma of the stalk, and this must, certainly,
be in considerable quantity, when the extraordinary
abundance of zooids is borne in mind.
When the zooid is strongly contracted, it forms a
nearly spherical prominence; in whose middle, a small round
aperture, or oblong fissure is observable (fig. 5(5, b), and,
in one of our specimens, almost all of the zooids are
contracted in this way; only, on vigilant examination,
are a few found, which have the tentacle half extended.
Whenever the tentacle is somewhat extended, the body
elongates (fig. 56, c), and when fully extended, the body of the
zooid has an ovate form (fig. 56, <l). The tentacle is
moveable in almost all directions; and from it’s sides, long
papil-lous pinnules issue, imparting a ranious appearance to it
(fig. 56, J). These pinnules are not found in all, but when
they are found and that is, very frequently; they have
the same structure as the tentacle, and are hollow, and
they correspond with the cavity of tins tentacle, and,
can lie retracted or extended, according to circumstances.
No opening on their rounded extremity could be
observed. Fig. 5(i gives a good illustration of these
remarkable zooids in their various forms, according, as they are
more or less extended.
The calcareous axis extends itself from the base of
the stalk, to it’s superior extremity. It is thickest at the
superior part of the bulbous portion, from which point, it
diminishes in thickness, both upwards and downwards. For
the greater part of it’s length, it is quadrangular, and has 4
deep lateral grooves, of which, that on the ventral side is
somewhat wider than the others, and it, also, has 4
rounded corners (fig. 61). The axis becomes in its superior
and inferior parts, gradually, more and mort; round, and
it’s grooves quite disappear (figs. 62. (53). In the inferior
half of the bulb, the axis lies in the dorsal canal, where,
<< prev. page << föreg. sida << >> nästa sida >> next page >>
