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70
dommeligt udviklet Epignath. Basaldelens 1ste Led er
ganske kort, dobbelt saa bredt som langt og er maaske
egentlig at betragte som Sternaldelen af et særskilt
Segment. Dens 2det Led er bredt bagtil, men afsmalnes
hurtigt fortil, idet den ydre Kant er skraat afskaaret; indad
lober det ud i eu oval. i Enden med korte Borster og
Torner besat Tyggeplade. Palpen er længere end
Basaldelen og alle dens 4 Led laiuelløse samt i den indre Kant
besat med indadkrummede Borster. Af Leddene er det
2det størst: sidste Led er skraat afskaaret i Enden og her
forsynet med 7 boiede Borster. Den mærkværdigt
udviklede Epignath udspringer fra Basaldelens 1ste Led med en
tyk. muskuløs Stilk og er ligesom Palpen paa 1ste Par
Kjæver ganske skjult i Gjellehulen, hvori den danner et
Ventilapparat, der ved sine rythmiske Svingninger frem og
tilbage underholder en stadig Strømning af Vandet i en
bestemt Betning. Dens ydre Parti dannes af en bred, stærkt
buet Plade af oval Form og membranøs Beskaffenhed, der
bagtil ender med et tyndt, snærtformigt Appendix. Noget
foran Midten er denne Plade forsynet med en tydelig
Tvær-sutur. hvorved den deles i 2 Segmenter. Det foran Suturen
liggende Segment er i Kanterne meget tint cilieret. Den
hele Epignaths Homologi med Gjelleapparatet hos
Cuma-ceerne er evident saavel ifølge dens Structur som
Beliggenhed og Forhold til Kjævefødderne.
Af Fødderne er de 2 forreste Par. ligesom’ hos Slægten
Apseudes. eiendommeligt udviklede, medens de 5 bagerste
Par er af mere normal Bygning og forestiller de egentlige
Gangfødder.
1ste Fodpar (Fig. 17). der udspringer fra den bagerste
Del af Hovedsegmentet, til liver Side af den før omtalte
transversale Chitinplade, er udviklet til særdeles kraftige
Griberedskaber i Lighed med de saakaldte Fangarme hos
høiere Krebsdyr (Decapoda). De viser en temmelig’stærk
Sformig Krumning og er bøiede ind under Forkroppen
saaledes, at deres Endeparti let kan bringes i Berørelse med
Mundaabningen. Man kan paa dem adskille 6 Led. hvoraf
de 2 sidste tilsammen danner en vel udviklet Sax. 1ste
Led er stærkt indknebet ved Basis, men derpaa meget
opsvulmet og fyldt meel kraftige Muskler, der tjener til at
bevæge den øvrige Del af Foden: det bærer ved Boden
paa den ydre Side et lidet 2-leddet. med 4 lange cilierede
Børster endende Appendix (Fig. 19). der aabenbart svarer
til den saakaldte Exopodit hos høiere Crustaceer
iSchizo-poder og Cumaeeer), og som vi bos Slægten Apseudes ogsaa
gjentinder paa det følgende Fodpar. 2det Led er ganske
og aldeles rudimentært og saa lidet, at det let undgaar
Opmærksomheden, ihvorvel dets Tilstedeværelse med fuld
Sikkerhed kan paavises. 3die Led er meget smalt, men
noget udvidet mod Enden og her ved en meget skjæv Sutur
forbundet med det næste. Dette er omtrent af
Basalleddets Længde, men betydelig smalere, noget sammentrykt
fra Siderne og i den nedre eller indre Kant forsynet med
4 stærke Børster. Den følgende Del af Foden, der fore-
and a peculiar-developed epignath. The lst joint of the
basal part is quite short, twice as broad as long, and should,
perhaps, strictly, be regarded as the sternal portion of a
separate segment. The 2nd joint is broad posteriorly,
rapidly tapering however anteriorly, the outer side being
obliquely truncate; inward, it protends as an oval masticatory
plate, beset at the extremity with short bristles and spines.
The palp is longer than the basal part, and has each of
its 4 joints lamellar, and armed along the inner margin
with incurving bristles. Of the joints, the 2nd lis the
largest: the terminal joint is obliquely truncate at the
extremity. where it has 7 curving bristles. The remarkably
developed epignath takes its origin on the 1st joint of
the basal part, as a thick, muscular stem, and. like the
palp on the 1st pair of maxillæ. is entirely concealed
within the branchial cavity, where it forms a ventilatory
apparatus, which, by rhythmical vibrations backward and
forward, produces an uninterrupted current of water in a
given direction. Its outer part is composed of’ a broad,
very considerably arcuate plate, oval in form and of a
membranous character, terminating posteriorly with a narrow,
digi-tiform appendix. A little anterior to the middle, this plate
exhibits a distinct transverse suture, dividing it into 2
segments. The segment in advance of the suture is verv finely
ciliated along the margins. The homology of this epignath
with the branchial apparatus in the Cumacea is indisputably
apparent, alike from the structure of the organ and its
position and relation to the maxillipeds.
Ol’ the legs, the 2 foremost pairs exhibit, as in the
genus Apseudes, a very peculiar development, whereas the
ö hindmost pairs are more normal in structure, and represent
the true pereiopoda.
The 1st pair of legs (fig. 17), springing from the
posterior part of the cephalic segment, on either side of
the previously mentioned chitinous plate, are. like the
so-called chelipeds in more highly developed Crustaceans
(Decapods) exceedingly powerful prehensile organs. They
exhibit a comparatively strong S-shaped curve, and are
bent in under the body, so ns to readily admit of their
terminal part being brought in contact with the buccal
orifice. They are composed of ü joints, the last two
forming together a well-developed chela. The 1st joint is very
much constricted at the base, from thence however greatly
swollen, containing as it does the powerful muscles that
serve for moving the other part of the leg; it bears at
the base, on the outer side, a small, two-jointed appendix,
terminating in 4 long, ciliated bristles (fig. 19), which
obviously correspond to the so-called exopodite in more highly
developed Crustaceans (Schizopods and Cuinaeeans). and
that, in the genus Apseudes. we also observe on the
succeeding pair of legs. The 2nd joint is quite rudimentary,
and so very small that it easily escapes observation, though
its presence can be determined with perfect certainty. The
3rd joint is exceedingly slender, but somewhat dilated
toward the extremity, where a very oblique suture connects
it with the succeeding one. The latter is about equal in
length to the basal joint, hut much more slender, somewhat
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