feestet helt oppe ved Basis til Yderkanten, en anden 
helt nede ved det ydre Hjorne, medens de 2 ovrige 
udgaar fra den nederste Del af Inderkanten. Den 
ydre Gren er temmelig smal, men successivt noget 
bredere mod Enden, og har langs Yderkanten en 
regelmessig Rad af circa 20 korte Torner, hvorpaa 
folger, festet til en seregen Afsats, en betydelig 
steerkere saadan. Fra den noget skraat afkuttede 
Ende udgaar 3 sterke divergerende Torner, hvoraf 
den yderste er lengst, den midterste kortest. Hele 
den indre Kant af Grenen er forovrigt besat med 
en tet Rad af lange og tynde cilierede Borster. 
Den indre Gren er betydelig lengere og ogsaa sma- 
lere end den ydre, nesten lineer, og viser ved 
Basis et ufuldstendigt sondret lidet Rodled. Den 
er i begge Kanter forsynet med en Rad af lignende 
Svommeborster som paa den ydre Gren og gaar ved 
Enden ud i en kort dolkformig Spids, indenfor hvil- 
ken en lang bagudrettet Torn er festet. 
Paa de ovrige Svommefodder (Fig. 9) er Basal- 
delen kortere og bredere, mere affladet, og har Yder- 
kanten tilskjerpet samt endende nedad med et spidst 
udtrukket Hjorne. Inderkanten er ligesom Yder- 
kanten uden Torner, men har 2 Knipper af meget 
fine Borster, skilte ved et lengere Mellemrum. Mel- 
lem de 2 Grene danner Basaldelen et lancetformigt 
tilspidset Fremspring. Den ydre Gren er forholds- 
vis storre og bredere end paa iste Par og har langs 
Yderkanten 7 Afsatser, hvet beveebnet med 2 teet 
sammenstillede divergerende Torner; fra Spidsen ud- 
gaar, som paa Iste Par, 3 Torner, som her succes- 
sivt tiltager i Lengde indad. Den indre Gren er 
kun lidet lengere end den ydre, men betydelig sma- 
lere, forovrigt af samme Beskaffenhed som paa Iste 
Par. Det bagerste Par skiller sig neppe fra de 2 
foregaaende uden derved, at det er noget mindre. 
De 2 Par rudimentere Bagkropslemmer, der er 
feestede til Bugsiden ved Enden af 5te og 6te Seg- 
ment (se Tab. I, Fig. 1), er begge af meget enkel 
Bygning og som det synes ganske ubevegelige. 
[ste Par (Tab. III, Fig. 10) er det storste og be- 
staar hvert af 2 Segmenter, et kort Basalled og et 
mere langstrakt, i sin ydre Del lidt udvidet Ende- 
led. Dette sidste er langs Inderkanten besat med 
fine Berster og har langs den skraat afskaarne Ende- 
rand en Rad af 7 Torner, hvoraf den yderste er 
leengst; mellem Tornerne bemerkes ogsaa en Del 
fine lige udad rettede Borster. — 2det Par (Fig. 11) 
er neppe mere end halvt saa lange som Iste og be- 
staar hvert af et enkelt ovalt Led, hvis Inderkant 
er ret, medens Yderkanten er noget buet. Til den 
20 
mity, and armed with 4 long spines, of which one 
is secured to the outer edge, quite up at the base; 
another quite down at the outer corner, whilst the 
2 others issue from the lowest part of the inner 
edge. The outer branch is pretty narrow, but is 
somewhat more successively broad towards the ex- 
tremity, and has a regular series of about 20 short 
spines along the outer edge, succeeded by a consi- 
derably more powerful one secured to a special pro- 
jection. From the somewhat obliquely truncated 
extremity there issue, 3 strongly divergent spines, 
of which the outermost one is the longest, and the 
medial one shortest. The entire inner edge of the 
branch is otherwise beset with a close series of long 
and slender ciliated bristles. The inner branch is con- 
siderably longer and also narrower than the outer 
one, almost linear, and exhibits at the base an 
imperfectly separated, small basal joint. It is fur- 
nished on both edges with a series of similar swim- 
ming bristles as on the outer branch, and at its 
extremity passes into a short lanceolate point, inside 
of which a long spine, directed backwards, is 
secured. : 
On the other swimming feet (fig. 9) the basal 
part is shorter and broader, more flattened, and has 
the outer edge sharpened and terminating down- 
wards in'an acutely drawn out corner. The inner 
edge, like the outer one, is devoid of spines, but has 
two bundles of very fine bristles, separated by a 
longish interval. Between the two branches the 
basal part forms a lanceolate pointed projection. 
The outer branch is relatively larger and broader 
than in the Ist pair, and has 7 projections along 
the outer edge, each of which is armed with 2 diver- 
gent spines placed closely to each other; from the 
point thére issue, as in the 1st pair, 3'spines, which 
increase here successively in length inwards. The 
inner branch is only a little longer than the outer 
one, but considerably narrower; otherwise of the 
same character as in the Ist pair. The last pair 
are scarcely distinguished from the 2 preceding ones, 
unless in that they are somewhat smaller. 
The 2 pairs of rudimentary, posterior append- 
ages of the body, which are secured to the ventral 
side at the extremity of the 5th and 6th segments 
(see Pl. I, fig. 1), are both of very simple structure, 
and, as it appears, quite immobile. The 1st pair (Pl. 
ITI, fig. 10) are the largest, and each consists of 2 seg- 
ments, a short basal joint and a more: elongated, in 
its outer part slightly widened, terminal joint. This 
last is beset along the inner edge with fine spines, 
and along the obliquely truncated terminal margin 
has a series of 7 spines, of which the outermost one 
is the longest; between the spines there are observed, 
also, a number of fine bristles directed straight 
outwards. The 2nd pair (fig. 11) are scarcely more 
than half as long as the Ist, and each consist of a 
