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9
Legemet er (se Pl. I, fig. 1) af ualmindelig
undersætsig og sammentrængt Form. samt ved vel markerede
Suturer delt i 6 paa hinanden følgende Afsnit eller
iSeg-menter, hvoraf det forreste forestiller Snabelen, det
bagerste Halesegmentet. Ethvert af de 4 midterste Segmenter
udvider sig til Siderhe til en lcort og tyk, i Enden afkuttet
Fortsats. hvortil Gangfødderne er festede. Disse laterale
Fortsatser er tret sammentrængte og kun skilte ved yderst
smale, spaltformige Mellemrum, hvorfor Legemets Midtparti
antager en temmelig bred, oval, noget nedtrykt Form.
Det bagerste Par af Sidefortsatserne er betydelig kortere
end de øvrige og kun skilte bagtil ved et smalt Indsnit,
fra hvis Bund Halesegmentet udgaar. Det forreste af de
egentlige Kropssegmenter. det saakaldte Hovedsegment, der
egentlig maa opfattes som fremkommet ved en
Sammensmeltning af flere Segmenter, er som sædvanlig det største
og omtrent dobbelt saa bredt som langt. Dog er det
forreste Parti, eller Pandedelen, her langtfra saa udviklet
som hos de fleste øvrige Pycnogonideer og uden nogen
egentlig Hals. Det viser i Enden en kraveformig
Fortykkelse. der ligesom omfatter Roden af Snabelen (se ogsaa
Fig. 1 a og 1 f), og har oventil, i nogen Atstand fra
Forkanten en temmelig stærkt fremspringende, men i Enden
stumpt afrundet Knude (Øieknuden). Paa den øvre Flade
af denne Knude sees de 4 lindseformige Cornere, der med
sit underliggende Pigment fremstiller Dyrets Synsorganer.
Disse Corneæ er hos nærværende Art meget smaa og vidt
adskilte, samt ordnede 2 og 2 paa hver Side af Midtlinien
(se Fig. 1 b). Bag Øieknuden findes paa Legemets Rygside
langs Midtlinien en Række af 5 mere eller mindre høie,
stumpt koniske Fremspring (se Fig. 1 a), hvoraf de 2
tilhører Hovedsegmentet, ethvert af de øvrige et særskilt
Segment; de 3 midterste af disse Fremspring ei" altid de
største. Desuden findes ved Enden af Legemets
Sidefort-satser, ligeledes paa Rygsiden, en mere eller mindre
tydelig stump Knude. Halesegmentet (se Fig. 1 c) er
horizon-talt stillet og næsten af spadedannet Form, stærkt
indknebet ved Basis og successivt udvidet mod Enden, der er
næsten tvært afkuttet eller med en neppe mærkelig Vinkel
i Midten; dets Længde er omtrent lig de 2 foregaaende
Segmenter tilsammen.
Snabelen (se Fig. 1. 1 a og 1 f) udgaar i horizontal
Retning fra Enden af Hovedsegmentet, dog saaledes, at
dens Endeparti er svagt nedbøiet (sé Fig. 1 a). Den er
omtrent halvt saa lang som det øvrige Legeme og ved
Basis neppe meget smalere elid den forreste Del af
Hovedsegmentet. Af Form er den udpræget konisk og temmelig
stærkt afsmalnende mod Enden, med det ydre Parti smalt
udtrukket og af cylindrisk Form. Ovenfra eller nedenfra
seet viser Snabelens Sidecontourer en svag dobbelt
Ind-bugtning, som ogsaa er bemærket af Wilson. Paa Spidsen
af Snabelen ligger Mundaabningen (se Fig. 1 f). som har
den sædvanlige trekantede Form, men mangler tydeligt
udviklede Læbeplader.
Pen norske Nordbavsexpedition. O. O. Sars: Pycnogonidea.
The body (see PI. 1. fig. 1) is remarkably thickset
and compact in form, and divided by well-marked sutures
into 6 consecutive parts, or segments, the foremost of
which represents the proboscis, the hindmost the caudal
segment. Each of the 4 median segments expand at the
sides, forming a short and thick truncate process, to which
the ambulatory legs are affixed. These lateral processes
lie crowded together, with but exceedingly narrow,
fissurelike intervals between; and hence the medial part of the
body assumes a rather broad, oval, somewhat depressed
form. The posterior pair of lateral processes are
considerably shorter than the rest, and separated behind by only
a narrow incision, from the bottom of which issues the
caudal segment. The most anterior of the true segments of
the body, the so-called cephalic segment, which, strictly, must
be regarded as a fusion together, so to speak, of several
segments, is as usual the largest, and aböut twice as broad
as long. Meanwhile the foremost or frontal part is in this
animal far from being so developed as in most other
Pycnogonids. and is also without any neck proper. It exhibits at
the extremity a collar-shaped inspissation, encompassing, as it
were, the base of the proboscis (see too fig. 1 a and fig.
1 f.), and having above, at some distance from the front
margin, a rather abruptly projecting, but at the extremity
rounded knob (the oculiferous tubercle). On the upper
surface of this protuberance are seen the 4 lenticular
corneæ, which, along with the underlying pigment, constitute
the visual organs of the animal. In the present species,
these cornere are exceedingly small and wide apart and
arranged, 2 and 2 together, on each side of the medial line (see
fig. 1 b). Behind the oculiferous tubercle, occurs on the dorsal
side of the body, along the medial line, a series of 5 more
or less elevated, obtuse conical projections (see fig. 1 a),
2 of which belong to the cephalic segment, each of the
others to a separate segment: the 3 middlemost of these
projections are invariably the largest. Moreover, at the
extremity of the lateral processes of the body, likewise on
the dorsal side, we observe a more or less distinct obtuse
protuberance. The caudal segment (see fig. 1 c). placed
horizontally, is almost spatulate in form, very much
instricted at the base, and expands successively towards the
extremity, which is nearly truncate or with a well-nigh
imperceptible angle in the middle; its length about equals
that of the 2 preceding segments taken together.
The proboscis (see fig. I. 1 a and 1 f) issues, with
a horizontal direction, from the extremity of the cephalic
segment, though in such manner as to give its terminal
part a slight downward bend (see fig. 1 a). It measures
about half the length of the rest of the body, and is at
the base very little if at all slenderer than the foremost
part of the cephalic segment. It has a marked conical
form and tapers rather abruptly towards the extremity,
with the outer portion slenderly produced and cylindrical
in form. Viewed from above or from below, the lateral
contours of (the proboscis exhibit a faint twofold curvature,
also noticed by Wilson. At the extremity of the
proboscis lies the buccal orifice (see fig. 1 f). which has the
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