60 
De ydre HalevedhaeUg (Pig. 19) liar Endeplaclerne 
temmelig store og brede. Den indre er omtrent l /*kortere 
end den ydre og lancetformig tilspidset saint riser ved Basis 
kun en yderst svag, neppe mserkelig Antydning til det for 
Familien characteristiske Horeapparat. Den ydre Plade er 
af aflang oval Form og viser i den ydre Kant nsermere 
Basis en liden med to Tornor bevsebnet Afsats ; foran denne 
er den ydre Kant ganske glat, medens disse Plader forpvrigt 
er rundtom borstebesatte. 
Hannen (Fig. 3) er adskilligt storre og kraftigere 
bygget end Hunnen og desuden let kjendeligt fra samme 
ved de tydeligt ndprsegede secundaere Kjonscharacterer. 
Iste Par Foleres Skaft (se fig. 20) er saaledes be- 
tydelig tykkcro og bar ved Enden under Svoberne det sied- 
vanlige baarede Appendix, der dog her er sserdeles kort, 
kuudeformigt og nassten ganske skjult af eller ligesom ind- 
samket i en fra Skaftet udgaaende Hudduplicatur. 
Svorumegrenene paa Kjsevefodderne og de egentlige 
Fodder er (se Fig. 3) forholdsvis endnu steerkere udviklede 
end hos Hunnen, med Basaldelen bredere og stserkere mu- 
skulos. 
Ved Basis af sidste Fodpar benuerkes de ydre Kjons- 
vedhseng i Form af to cybndriske, noget fortil krummede 
og i Spidsen med stive Borster besatte Lapper. 
Bagkroppen er forholdsvis kraftigere bygget end lios 
Hunnen, og dens Buglemmer samtlige udviklede til msegtige 
Svommeredskaber, med bred muskulos Basaldel og sserdeles 
langc, mangeleddede Endegrene. Den indre Gren er her 
paa alle Par, ogsaa paa lste (Fig. 21), af ens Udseende. 
Den er kjendeligt kortere end den ydre og danner ved Basis 
en oval, med nogle faa fine Borster besat pladeformig Ud- 
vidning. Den ydre Gren paa 2det Par (Fig. 22) er af 
enorm Laengde og delt i ikke mindre end 38 Led. hvoraf 
de ydre, istedetfor Fjserbprster, er forsynede med korte 
simple Torner. 
Farven saavol af Han som Hun er i levende Tilstand 
temmelig uniform lyserod eller kjodrod. Da imidlertid Le- 
gemet er temmelig gjennemsigtigt, skinner enkelte af de 
indre Dele og navnlig den store med mdrkerodt Indhold 
fyldte Mave, igjennem Jntegumenterne. 
NcervEerende Art opuaar en for en Myside colossal 
Storrelse, idet Hunnen har en Laengde af 64”™, medens 
Hannen bliver enduu adskilligt lsengere, nemlig indtil 70 mm . 
Forekomst. Fem mere eller mindre fuldstendige 
Exemplarer af denne maerkelige Form blev under Expedi- 
tionens sidste Togt optaget ved Hjmlp af Trawlnettet fra 
det enorme Dyb af lllOFavne i Havet NV. af[Finmarken 
(Stat. 295), og i det selvsamme overordentlig righoldige 
Kast, der blandt mange andre interessante Ting ogsaa bragte 
op det i det foregaaende omtalte Exemplar af den eien- 
dommelige Mysidcform, Pseudmnysis abyssi, ligesom ogsaa, 
de 4 pragtfulde Exemplarer af Bylhocaris leucopis. 
The outer caudal appendages (fig. 19) have the terminal 
plates comparatively large and broad. The inner is about 
one-fourth shorter than the outer, and lanceolate, exhibiting 
at the base an exceedingly faint, scarcely perceptible indi- 
cation of the auditory apparatus distinguishing the family. 
The outer plate is oblongo-oval in form, and bears on the 
outer margin, near the base, a small shelf, armed with two 
spines; anterior to this shelf, the outer margin is quite 
smooth, whereas the plates are elsewhere beset with bristles 
round the edges. 
The male (fig. 3) is considerably larger and more 
powerful in structure than the female, and, moreover, may 
be readily distinguished from the latter by reason of its 
prominent secondary sexual characters. 
Thus, the peduncle of the 1st pa ir of antennae (see fig. 20) 
is considerably thicker, and has at the extremity the usual hir- 
sute appendix, winch, however, is exceedingly short, tuber- 
culiform. and almost entirely concealed by, or rather sunk into, 
a thick integumental duplicating issuing from the peduncle. 
The natatory branches on the maxillipeds and the true 
legs (see fig. 3) exhibit comparatively a still more powerful 
development than in the female, having the basal part broader 
and more prominently muscular. 
At the base of the last pair of legs, are seen the 
outer sexual appendages, having the form of two cylindrical, 
somewhat anteriorly curved lobes, armed at the point with 
stiff bristles. 
The posterior division of the body is comparatively 
more robust in structure than in the female, and has all of 
its limbs developed as powerful natatory organs, with a 
broad, muscular basal part and exceedingly long, multi- 
articulate terminal branches. The inner branch on all the 
pairs, also the 1st (fig. 21). is uniform in appearance. It is 
appreciably shorter than the outer, and exhibits at the base an 
oval, lamelliform dilatation, beset with a few slender bristles. 
The outer branch on the 2nd pair (fig. 22) is of prodigious 
length, and divided into not less than 38 articulations, of 
which the outer, instead of having plumose bristles, are 
furnished with short, simple spines. 
The colour, both of the male and female, in a living 
state, is a comparatively uniform light-red, or pink. The 
body, however, being well-nigh translucent, some few of 
the inner parts, and more especially the large stomach, 
filled with a dark-red substance, are seen shining through 
the integuments. 
The present species attains, for a Mysidian, a • colossal 
size, the female reaching a length of 64"™, while the male 
has a still greater, viz. 70"”". 
Occurrence. — Five more or less perfect specimens 
of this striking form came up in the trawl, on the last 
cruise of the Expedition, from the prodigious depth of 1 1 10 
fathoms, in the open sea, north-west of Finmark (Stat. 
295), and in the same remarkably rich haul that, among 
other interesting objects, also brought to light the previously 
recorded specimen of the characteristic Mysidian, Pseudomysis 
abyssi, along with 4 magnificent specimens of Bythocaris 
I leucopis. 
