20 



fæstet helt oppe ved Basis til Yderkanten, en anden 

 helt nede ved det ydre Hjørne, medens de 2 øvrige 

 udsaar fra den nederste Del af Inderkanten. Den 

 3'dre Gren er temmelig smal, men snccessivt noget 

 bredere mod Enden, og har langs Yderkanten en 

 regelmæssig Ead af circa 20 korte Torner, hvorpaa 

 følger, fæstet til en særegen Afsats, en betydelig 

 stærkere saadan. Fra den noget skraat afkuttede 

 Ende udgaar 3 stærke divergerende Torner, hvoraf 

 den yderste er læugst, den midterste kortest. Hele 

 <len indre Kant af Grenen er forovrigt besat med 

 en tæt Rad af lange og tynde cilierede Børster. 

 Den indre Gren er betydelig længere og ogsaa sma- 

 lere end den ydre, næsten lineær, og viser ved 

 Basis et nfnldstændigt sondret lidet Rodled. Den 

 er i begge Kanter for.synet med en Rad af lignende 

 Svommebørster som paa den ydre Gren og gaar ved 

 Enden nd i en kort dolkformig Spids, indenfor hvil- 

 ken en lang bagudrettet Torn er fæstet. 



Paa de øvrige Svømmefodder (Fig. 9) er Basal-, 

 delen kortere og bredere, mere affladet, og har Yder- 

 kanten tilskjærpet samt endende nedad med et spidst 

 iidtrukket Hjerne. Inderkanten er ligesom Yder- 

 kanten uden Torner, men har 2 Knipper af meget 

 fine Borster, skilte ved et længere Mellemrum. Mel- 

 lem de 2 Grene danner Basaldelen et lancetformigt 

 tilspidset Fremspring. Den ydre Gren er forholds- 

 vis større og bredere end paa Iste Par og har langs 

 Yderkanten 7 Afsatser, hver bevæbnet med 2 tæt 

 sammenstillede divergerende Torner; fra Spidsen ud- 

 gaar, som paa Iste Par, 3 Torner, som her sncces- 

 sivt tiltager i Længde indad. Den indre Gren er 

 kun lidet længere 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 rudimentære Bagkropslemmer. der er 

 fæstede 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 ubevægelige. 

 Iste Par (Tab. III, Fig. 10) er det største og be- 

 staar hvert af 2 Segmenter, et kort Basalled og et 

 mere langstrakt, i sin ydre Del lidt ndvidet Ende- 

 led. Dette sidste er langs Inderkanten besat med 

 fine Børster og har langs den skraat afskaarne Ende- 

 rand en Rad af 7 Torner, hvoraf den yderste er 

 længst; mellem Tornerne bemærkes ogsaa en Del 

 fine lige udåd rettede Børster. — 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 



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 i.^sue, 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 1st 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 there 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 1st 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 PI. I, fig. 1), are both of very simple structure, 

 and, as it appears, quite immobile. The 1st pair (PI. 

 Ill, fig. 10) are the largest, and each consists of 2 seg- 

 ments, a shoi't basal joint and a more elongated, in 

 its outer part slightlj' 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 1st, and each consist of a 



