126 
Gen. 3. Ischnosoma, G. 0. Sars. 1866. 
Zoologisk Reise i 1 805. 
Slsegtscharacteristik. Legemet seerdeles smalt og for- 
lsenget, naisten cylindriskt, mere eller mindre starlet ind- 
knebet paa Midten og tykkeet i sin forroste Del. Hovedet 
forholdsvis lidet, med jevnt afrundet Panderand. 4de og 
5te Forkropssegment fast forbundne med hinanden og dan- 
nende tilsammen et saerdeles stserkt forlauiget og smalt cy- 
lindriskt eller timeglasformigt Afsnit. Bagkropssegmentet 
af oval Form, indknebet ved Basis. Ingen 0ine. lste Par 
Folere med Skaftets 2det Led stserkt forkenget og smalt, 
Svoben kort. 2det Par Folere betydelig laengere, med 
traadformig, mangeleddet Svobe. Kindbakkerne uden Palpe. 
lste Fodpar kort og undersaetsigt bygget, subprehensilt, de 
pvrige stserkt forlaengede og tynde med simpel Endeklo ; de 
3 bagre Par ved et botydeligt Mellemrum skilte fra de 4 
forreste. Halevedluengene simple. 
Bemserkninger. Nservaerende eiendommelige og fra 
de typiske Asellider i sit ydre meget afvigende Slsegt viser 
en vis habituel Lighed med enkelte til nseste Familie, Mun- 
nopsidse, borende Former, navnlig Arterne af Slmgten Des- 
mosoma, men kan dog ikke henfores til bin Familie, da de 
3 bagerste Par Fodder her ikke skiller sig i sin Bygning 
fra de foregaaende, men ligesom disse forestiller segte Gang- 
fodder. En anden ligeledes meget anomal Slaegt, som jeg 
tidligere urigtigt liar stillet sammen med Munnopsiderne, 
nemlig SI. Macro dylis, syncs livad den ydre Form angaar 
at danne et Slags Overgang til den mere normale nedtrykte 
Form, dor characteriserer de typiske Asellider. Den her 
omhandlede Slaegt indeholder for Tiden 2 distincte Arter, 
nemlig den forst opdagede typiske Form, J. bispinosum, fra 
den norske Kyst, og den nedenfor nsermene beskrevne nye 
Art. 
28. Ischnosoma qvadrispinosum, G. 0. Sars, n. sp. 
(PI. XI, Fig. 2(1—29) 
Ischiioso7iia q va drisp in o sum } Or. 0. Sars. Crustacea et Pycnogonida nova 
etc., No. 10. 
Artskarakteristik. Legemet overalt ru af smaa til- 
trykte Pigger. lste og 3die Forkropssegment til liver Side 
bevsebnede med en stserk fortilrettet Torn ; de paa lste Seg- 
ment storst. 4de og 5te Segment tilsammen indtagende 
omtrent Halvparten af Totallsengden. Bagkropssegmentet 
forholdsvis lidet, bagtil stumpt tilspidset. 2det Par Folere 
kortere end Legemet. lste Fodpar mindre kraftigt bygget 
end hos den typiske Art, med 4de Led lain lidet opsvul- 
Gen. 3. Ischnosoma, G. 0. Sars, 1866. 
Zoologisk Reise i 1805. 
Generic Character. — Body exceedingly slender and 
elongate, almost cvliiidric, more or less constricted in the 
middle, and thickset throughout the anterior part. Head 
comparatively small, with uniformly rounded frontal margin. 
Fourth and fifth segments firmly connected together, and 
constituting one with the other a very prominently elongated 
and narrow - cvliiidric , or rather hourglass - like section. 
Abdominal segment oval in form, constricted at the base. 
Ho eyes. First pair of antennae with 2nd joint of peduncle 
greatly produced and slender, flagellum short. Second pair 
of antennae considerably longer, with a filiform multi-artic- 
ulate flagellum. Mandibles without any palp. First pair 
of legs short, and thickset in structure, subprehensile, the 
others greatly produced and slender, with the terminal claw 
simple, the 3 posterior pairs Separated by a considerable 
interspace from the 4 anterior. Caudal appendages simple, 
Remarks. — The present characteristic genus, that in 
its outer habitus deviates very considerably from the typical 
Asellidfe, has a certain general resemblance to some of the 
forms comprised in the next family — the Munnopskke, more 
especially the species of the genus Desmosoma, yet cannot 
be referred to that family, since the 3 posterior pairs of 
legs exhibit no difference in structure from the preceding, 
but, like the latter, represent true pereiopoda. Another 
most anomalous form that I had erroneously classed along 
with the Munnopskke, viz. the genus Macrostylis, would 
appear, as regards its outer habitus, to constitute a kind 
of transition to the more normal, depressed form charac- 
terizing the typical Asellidse. The genus treated of here 
comprises at present 2 distinct species, viz. the typical form 
(that first discovered), J. bispinosum, from the Norwegian 
coast, and the new species described in detail below. 
28. Ischnosoma qvadrispinosum, G. 0. Sars, n. sp. 
(PI. XI, figs. 26 — 29) 
Ischnosoma qvadrispinosum, Gr. 0. Sars, Crustacea et Pycnogonida nova 
etc., No. 10. 
Specific Character. — Body everywhere rough, by 
reason of minute, appressed spikes. First and third seg- 
ments armed on' either side with a strong, anteriorly 
directed spine; those on the 1st segment largest. Fourth 
and fifth segments measuring together about one-half of 
total length. Abdominal segment comparatively small, 
with posterior extremity obtusely pointed. Second pair 
of antennae shorter than body. First pair of legs less 
