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(i 9
Kindbakkerne. der, naar Dyret sees nedenfra (se Fig. 3),
viser sig som to temmelig store couvexe Fremstaaenheder
til hver Side af Overlæben, er af temmelig kraftig Bygning
og stærkt incrusterede. Deres Corpora har (se Fig. 9) den
sædvanlige baaddannede Form og fyldes af de stærke
Ad-ductormuskler. der i Midten gaar over i en chitinagtig
Aponeurose. Deres indre Del gaar ud i 2 divergerende
Fortsatser, hvoraf den forreste gaar i lige Flugt med Corpus
og forestiller Kindbakkens egentlige Endeparti; den er noget
indadkrummet og i Enden delt i 2 tandbærende Plader,
der forholder sig noget ulige paa lioire og venstre
Kind-bakke (se Fig. 10). Paa venstre Kindbakke er begge Plader
omtrent ligestore og dækker hinanden gjensidig; paa liøire
Kindbakke er den bagerste meget liden, næsten cylindrisk
og ved Spidsen besat med nogle tine Torner. Lige bag
disse Plader tindes paa begge Kindbakker en Kad af simple
tornformige Borster. 4 paa høiere og 5 paa venstre. Den
bagre Fortsats, der udgaar fra Kindbakkens Corpus næsten
under en ret Vinkel, forestiller Tyggeknuden. Den er smalt
cylindrisk, noget tyndere mod Enden og her forsynet med
den sædvanlige riflede Sculptur. Kindbakkernes Palpe (Fig.
Ih er meget spinkel og kun yderst sparsomt børstebesat.
Den bestaar af 3 tydelige Led, hvoraf det 2det er længst
og ved Enden i den ene Kant forsynet med en enkelt kort
Børste. Sidste Led er ganske lidet, koniskt og ender med
2 noget stærkere Borster.
Iste Par Kjæver (Fig. 12) har 2 tydeligt udviklede
fortilrettede Tyggelapper, hvoraf den ydre er stærkest og
paa Enden bevæbnet med talrige spidse Torner, medens
den indre er af membranos Beskaffenhed, tungeformig og
ved Spidsen forsynet med 4 cilierede Børster. Fra
Ydersiden af Basaldelen udgaar en lige bagudrettet Gren (Palpe),
eier bestaar af 3 utydeligt begrændsede Segmenter og ved
Spidsen er forsynet med 3 stærke indadkrummede Borster.
Denne Gren rager, ligesom Epignathen paa Kjævefødderne,
frit frem i Gjellehulen og synes nærmest bestemt til at rense
samme for fremmede Partikler.
2det Par Kjæver (Fig. 13) er smaa, men normalt
udviklede. Den noget pladeformige Basaldel danner indad en
stump Vinkel og har foran denne en tæt Besætning af fine
Børster. Fortil gaar den ud i en kort afstumpet Tyggelap,
der foruden med Børster er bevæbnet med 3 stærke, i den
ene Kant grovt tandede Torner ise Fig. 14i. Det ydre
Parti af Kjæven. der ved en tydelig Sutur er begrændset
fra Basaldelen, bestaar af 2 Led, hvoraf det 1ste indad
løber ud i en lignende Tyggelap. som den Basaldelen
tilhorende, men kun besat med simple Børster. Endeleddet
er ganske lidet og forsynet med 5 noget stærkere Børster,
ordnede i 2 Knipper.
Kjævefødderne (Fig. 15), som delvis dækker Kjæverne
nedad (se Fig. 3), bestaar af en 2-leddet pladeformig
Basaldel. som er fast forbunden men den tilsvarende paa den
anden Side, en 4-leddet Endedel eller Palpe og en eien-
The mandibles, which, on viewing the animal from
below (fig. 3). present the appearance of two comparatively
large convex protuberances, one on either side of the labrum.
are powerful in structure, and very considerably incrusted.
Their corpora (see fig. 9) have the usual navicular form, and are
tillod up with the strong adductor muscles, which, in the middle,
pass into a chitinous aponeurosis. Their inner part branches
out into 2 diverging projections, of which the more anterior
protends in the same plane as the corpus, and. strictly,
represents the terminal part of the mandible: it is somewhat
incurved. and divided at the extremity into 2 dentiferous plates,
differing slightly in character on the right and left mandibles
(see tig. 10). On the left mandible, the plates are about
equal in size, the one covering the other: on the right
mandible, the posterior one is very small, almost cylindric, and
at the point beset with a few slender spines. Immediately
posterior to these plates, on both mandibles, is seen a row of
simple spiniform bristles, 4 on the right and 5 on the left.
The posterior projection, jutting out almost at right angles
from the corpus of the mandible, represents the molar
protuberance. It is slender-cvlindric. somewhat slimmer toward
the extremity, where it has the usual grooved sculpturing.
The palp of the mandibles (tig. 11) is exceedingly slender,
and but sparingly furnished with bristles. It consists of
three distinct joints, of which the 2nd is the longest, and
has on one of the margins, at the extremity, a single short
bristle. The last joint is quite small, conic, and terminates
with 2 somewhat stronger bristles.
The 1st pair of maxilhe i fig. 12) have 2 distinctly
developed, anteriorly directed masticatory lobes, of which
the outer one is the stronger, and furnished at the extremity
with numerous acute spines, while the inner lobe is of a
membranous character, linguiform. and armed at the point
with 4 ciliated bristles. From the outer side of the basal
part proceeds a posteriorly directed branch (the palp),
composed of 3 indistinctly defined segments, and furnished at
the point with 3 strong, inward-curving bristles. This
branch — as does also the epignath on the maxillipeds —
projects freely into the branchial cavity, its chief function
being apparently to cleanse the latter from detrimental
particles.
The 2nd pair of maxillæ (fig. 13) are small, but
normally developed. The somewhat lamelliform basal part
forms inward an obtuse angle, anterior to which it has
a dense armature of slender bristles. Anteriorly, it juts
out as a short, truncate masticatory lobe, armed, exclusive
of bristles, with 3 strong, on one side coarsely dentate, spines
(see fig. 14). The outer portion of the maxilla, separated
by a distinct suture from the basal part, consists of 2 joints,
of which the 1st protends inward as a masticatory lobe, similar
to that on the basal part but furnished merely with simple
bristles. The terminal joint is quite small, and armed with
5 somewhat stronger bristles, arranged in 2 bunches.
The maxillipeds (fig. 15), which, below, partially cover
the maxillæ (fig. 3), consist of a two-jointed, lamelliform
basal part, firmly connected with that corresponding to it
on the opposite side, a four-jointed terminal part, or palpi
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