Det paa Hovedet folgende Kropsafsnit, Midt- 
kroppen eller Truncus, er fortil omtrent af Hovedets 
‘Brede og lidt nedtrykt, men afsmalnes lidt i sin 
bagerste Del. Det er sammensat af 11 paa hinanden 
folgende korte og ensformigt udviklede Segmenter, 
hvoraf ethvert berer et Par Branchialfodder. Disse 
sidste folger med regelmessige korte Mellemrum 
efter hinanden, dannende med sine forskjellige Lap- 
per og talrige Borster til hver Side en bred Breemme. 
Herved fremkommer langs Midtkroppens Underside 
en af samtlige Branchialfodder begrendset kanal- 
agtig Fordybning, der gradvis tiltager noget i Brede 
fortil, hvor den stoder op mod Mundregionen. 
Bagkroppen eller Halen er overordentlig slank, 
betydelig smalere end Midtkroppen, og af regelmes- 
sig cylindrisk Form. Den udgjor kjendeligt mere 
end Halvdelen af Legemets Totallengde, og er sam- 
mensat af 9 Segmenter foruden Halegrenene. Af 
disse Segmenter er de 2 forreste kun i den dorsale 
Del tydeligt sondrede, medens de ventralt gaar over 
i hinanden og danner her Udspringet for de ydre 
‘Kjonsvedheng. Disse 2 forste Segmenter af Halen 
vil derfor passende kunne benevnes: «Kjonsringene». 
Hos Hunnen er det forreste af disse Segmenter noget 
opsvulmet fortil, og det bagerste danner nedentil, 
ved Basis af Hgbeholderen, 2 rundagtige Fremspring, 
der navnlig- er meget tydeligt fremtredende, naar 
Dyret sees ovenfra eller nedenfra (se Tab. VI, Fig. 4, 
Tab. VIL, Fig. 11). De folgende 5 Segmenter er 
alle af ens Udseende og ogsaa af tilnermelsesvis 
samme Storrelse, simpelt cylindriske, med Lengden 
betydelig sterre end Breden. Nestsidste Segment 
er derimod betydelig lengere end de ovrige, og sidste 
omvendt meget kort, neppe mere end halvt saa langt 
som nestsidste. Det er (se Tab. VI, Fig. 10) tveert 
afkuttet. i Enden og viser i Midten af den bagre 
Kant en ganske svag Indbugtning. Til hver Side 
_af denne, og adskilte i Midten ved et storre Mellem- 
rum, er festet de smalt lancetformige Halegrene, 
der maaske, i Lighed med den saakaldte Furca hos 
Copepoderne, kan betragtes som fremkomne ved Klov- 
 ningen af et terminalt Segment, men som dog vel 
correctest vil kunne beskrives som et Par omformede 
Lemmer. : 
Hunnens Lengde gaar op til 18 mm. -Hannen 
er i, Regelen kjendelig storre og opnaar ofte en 
Lengde af indtil 23 mm. Begge Kjon er desuden let 
kjendelige ved den meget forskjellige Udvikling af 
2det Par Foiere, samt ved Beskaffenheden af de 
ydre Kjonsvedheng. Disse vil tea gp kunne be- 
a paa dette Sted. 
43 
maxillee 
ment. 
The division of the body that succeeds the 
head, the mesosome or truncus, is about same 
breadth in front as the head, and a little flattened, 
but narrows a little in its backmost part. It is 
composed of 11 short and uniformly developed seg- 
ments, of which each carries a pair of branchial 
feet. These last follow after each other at regular 
issue ventrally from the cervical seg- 
. short intervals, forming with their various lobes 
and numerous bristles a broad fringe on either 
side. In this way there is produced along the un- 
derside of the mesosome a canalular cavity, borde- 
red by all the branchial feet, which gradually in- 
creases somewhat in breadth in front, where it 
joins up to the oral region. 
The metasome or tail is extraordinarily slen- 
der, considerably narrower than the mesosome, and 
of regular cylindrical shape. It occupies appreciably, 
more than half the entire length of the body, 
and is composed of 9 segments besides the caudal 
rami. Of these segments, the 2 foremost ones 
are only distinctly separated in the dorsal part, 
whilst they ventrally pass over into each other, and 
_ form here the origin of the outer sexual appendages. 
These 2 first segments of the tail may, therefore, sui- 
tably be named «the sexual segments». In the female 
the foremost of these segments is somewhat swollen 
in front; and the backmost forms downwards, at 
the base of the marsupium, 2 roundish prominences, 
which are, especially, very distinctly prominent when 
the animal is viewed from above or from below (see 
Pl. VI, fig. 4, Pl. VIII, fig. 11). The succeeding 
5 segments have all a uniform appearance, and are 
also of approximately the same size, plain cylin- 
drical, with the length considerably greater than 
the breadth. The penultimate segment is, on the 
contrary, considerably ‘longer than the others, while, 
on the other hand, the last is very short, scarcely 
more than half as long as the penultimate one. It 
is (see Pl. VI, fig. 10) transversally truncated at 
the extremity, and in the middle of the posterior 
edge shows a quite faint sinus. -On either side 
of this, and separated in the middle by a lar- 
gish interval, the narrow lanceolate caudal rami 
are attached,” which, perhaps, like the so-called 
furca in the Copepods, may be considered as pro- 
duced by the splitting of a terminal segment, but 
which, however, probably more correctly may be 
described as a pair of transformed appendages. 
The length of the female reaches up to 18 m. m. 
The male is, as a rule, appreciably larger, and fre- 
quently attains a length of 23 m..m. Both sexes 
are, further, easily recognizable by the very different 
development of the 2nd pair of antenne, and by 
the character of the outer sexual appendages. These 
may be conveniently described here. 
