78 
Lsengden af Hunnen er af Hannen ubetydelig 
mindre. Naervaerende Art borer saaledes til de storste i 
denne Familie. 
Forekomst og Udbi’edning. 2 Exemplarer, en Hun 
og en Han af den ovenbeskrevne Tanaide blev under Ex- 
peditionens lste Togt optaget i Bundskraben fra et Dyb af 
417 Eavne udenfor Storeggen (Stat. 31). Under 2det Togt 
erkoldtes enkelte Exemplarer af samme Art paa 2 andre 
Lokaliteter (Stat. 124 og 248), begge beliggende i Havet 
udenfor Kysten af Helgoland. Dybden fra 350 til 778 
Eavne. Alle 3 Stationer tilhorer den kolde Area. 
Artens for Tiden bekjendte TJdbredningsfelt er saaledes 
det store Havdyb udenfor X orges Yestkyst fra den 63de 
til den 68de Bredegrad. Men efter al Rimeliglied er den 
en a?gte arktisk Form, der vistnok vil vise sig at forekomme 
paa mange andre Steder i den kolde Area’s Dyb. 
Gen. 2. Leptognatliia, G. 0. Sars. 1881. 
Revision af Gruppen Isopoda olielifera, 
Slsegtscharacteristik. Legemet bos Hunuen mere eller 
mindre langstrakt og smalt, med skarpt begramdsede Seg- 
menter. bos Hannen betydelig kortere. Ingen 0ine eller 
Dienlober. lste Par Fplere bos Hunnen 4-leddede, hos 
Hannen betydelig storre. med tykt 3-leddet Skaft og 4-leddet 
Svobe forsynet med teette Knipper af 'Sandsebprster. Kind- 
bakkerne meget smaa og svage. med fligformig tilspidset 
Tyggefortsats. Saxfodderne noget ulige bos Han og Hun, 
Saxen bos Hunnen kraftigt udviklet af trianguber Form, 
hos Hannen betydelig svagere, med den ubevmgelige Finger 
kortere end den bevasgelige. Gangfpdderne forholdsvis meget 
smaa og spinkle, de 3 bagerste Par noget nlig de foregaa- 
ende og bevahnede med staerke Tomer. Bagkroppens Bug- 
lemmer saavel bos Han som Hun vel udviklede, med ovale, 
tset bprstebesatte Endeplader. Halevedhaengene tvegrenede, 
med den ydre Gren meget liden. undertiden ganske rudi- 
meutaer, den indre bos Hunnen 2-leddet. hos Hannen 3-leddet. 
Hunnens Brystpose af normal Bygning. 
Bemserkninger. Denne Shegt udmrerker sig ister ved 
Kindbakkernes eiendommelige Udseende og svage Bygning, 
hvilket bar givet Anledning til Slsegtsnavnet. Fra foregaa- 
ende Slffigt, med hvilken den i Felonies Bygning stemmer 
overens. skiller den sig blandt andet vaeseutlig derved, at 
Bagkroppens Buglemmer bos Hunnen er [vel udviklede og 
forsynede med borstebesatte Endeplader. 
Slsegten er temmelig artsrig, idet jeg liar kannet hen- 
fpre til samme ikke mindre end 10 forskjellige Arter. De 
Length of female of male but very little less. 
The present species ranks accordingly as one of the largest 
in this family. 
Occurrence and Distribution. Two specimens, a 
female and a male, of the Tanaid described above, were 
brought up. on the 1st cruise of the Expedition, in the 
dredge, from a depth of 417 fathoms, off the Storeggen 
bank (Stat. 31). On the 2nd cruise, a few specimens were 
obtained of the same species at 2 other localities (Stats. 
124, 248), both in the open sea, off the coast of Helgeland, 
depth from 350 to 778 fathoms. All 3 Stations in the 
cold area. 
Hence, the tract throughout which the species is at 
present known to be distributed coincides with the great 
ocean depths off the West Coast of Norway, extending from 
the 63rd to the 68th parallel of latitude. But. in all 
probability, it is a true Arctic form, that uo doubt will 
be found to occur in many other parts of the cold area. 
Gen. 2. Leptogriatliia, G. 0. Sars, 1881. 
Revision af Gruppen Isopoda chelifera. 
Generic Character. — Body in female more or less 
elongate and slender, with sharply defined segments ; in 
male considerably shorter. Xo eyes or ocular lobes. First 
pair of antenna? in female four-jointed, in male consider- 
ably larger, with a thick, three-jointed peduncle, and a four- 
jointed flagellum furnished with dense fascicles of sensory 
bristles. Mandibles very small and weak, with an acutely 
lobular molar projection. Chelipeds somewhat dissimilar 
in male and female. Chela in female powerfully developed, 
triangular; in male much more feeble, with the immov- 
able finger shorter than the movable. Ambulatory legs 
comparatively very small and fragile, the 3 posterior pairs 
somewhat unlike the preceding, and armed with stronger 
spines. Pleopoda both in male and female well developed, 
with ovate, closely setiferous terminal plates. Caudal 
appendages biramous. with the outer branch very small, 
sometimes quite rudimentary, the inner, in female, two- 
jointed, in male three-jointed. Marsupium of female normal 
in structure. 
Remarks. — The genus is distinguished more par- 
ticularly by the peculiar appearance and feeble structure of 
the mandibles, from which its generic appelation is derived. 
From the preceding genus, with which it agrees in the 
structure of the antennae, it differs, among other charac- 
teristics, chiefly in the pleopoda of the female being well 
developed and furnished with setiferous terminal plates'. 
The genus may be regarded as rich in species, since 
I have been able to class under it not less than 10 different 
