31 



regelmæssig svingende rythnnsk Bevægelse, som kun j 

 for kortere Tid ganske kan stoppes. Denne Be- 

 vægelse har væsentlig respiratoriske Formaal, men 

 er ogsaa af stor Betydning for Næringsoptagelsen. 

 Ved disse Lemmers Spil frembringes nemlig inden- 

 for Rygskjoldets Val vier en fertil gaaende Strøm- 

 ning af Våndet, hvormed de Smaapartikler, der tje- 

 ner Dyret til Fode, hvirvles indenfor Munddelenes 

 Oraraade. Våndet strømmer herunder i en conti- 

 nuerlig Strom ud fra Rygskjoldets forreste Ende, 

 nedenfor Pandepladen. Derfor holdes denne altid, 

 Tinder BranchialfoddernesBevægelse, lige fortil strakt, 

 medens den i Regelen, saasnart Bevægelsen stopper, 

 boies nedad, hvorved den som en Klap tillukker den 

 forreste Aabning af Rygskjoldet. 



Udbredning. Arten synes at have en ganske 

 overordentlig vid geograjihisk Udbreduing. Foruden 

 ved Norges Kyster er den observeret i de arktiske 

 Have, ved Gronland, Spitsbergen og Island, frem- 

 deles ved Nordamerikas Østkyst, ved de britiske 

 (Jer, og idethele langs hele Europas Nordsø- og 

 Atlanterhavskyst, ligesom den ogsaa forekommer i 

 Middelhavet, hvor den paa sine Steder, som i Golfen 

 ved Neapel, ikke er ualmindelig. 



2. Xebalia typhlops, G. 0. Sårs. 



(PI. 1, Fig. 4, Pl. IV, Fig. '.)— li)). 



Nehalla tyxihlops, G. 0. Sårs, Nye Pybvandscrustaceor fra Lo- 

 foten; Chr. Vid. Selsii. Forh. f. 1869. 



Artscharacteristik, Meget lig foregaaende Art 

 i sin almindelige Habitiis, skjondt maaske lidt mere 

 vindersætsig af Form. Rygskjoldet, seet fra Siden, 

 af oval Form, lidt lavere fortil og med de nedre 

 Kanter jevnt buede paa Midten. Pandepladen vel 

 udviklet, aflang oval, stærkt hvælvet oventil og for- 

 synet i Enden med et spidst tornformigt Fremspring, 

 Øinene yderst smaa og rudimentære, koniskt til- 

 lobeude i Enden, og uden Spor af Pigment eller 

 Synselementer. De øvre Følere (høs Hunnen) for- 

 holdsvis kortere end hos foregaaende Art, med Svo- 

 ben neppe længere end Skaftet og kun sammensat 

 af 10 Led, det bladformige Appendix temmelig for- 

 længet, næsten halvt saa langt som Svøben. De 

 nedre Folere omtrent som hos N. hipes. Branchial- 

 fodderne med Endopoditen meget tyiid og stærkt 

 forlænget, ombøiet i Spidsen og forsynet med lange 

 divergerende Fjærbørster; Epipoditen med den dor- 



of life, and may through the semi-transparent inte- 

 guments observe the pulsations of the heart, the 

 peristaltic movements of the intestine, and the play 

 of the branchial feet. These last, which have no 

 influence whatsoever on the locomotion, we will 

 usually find in a regvilar, swinging, rythmical mo- 

 tion, which only for a short time may be quite 

 stopped. That motion has chiefly a respiratory func- 

 tion, but is also of great impoitance in securing 

 the nourishment. By the plaj^ of these appendages 

 there is produced, namely, inside of the valves of 

 the carapace, a forward current of the water by 

 which the small particles that serve the animal for 

 food are drawn within the area of the oral parts. 

 The water during this flows out in a continuous 

 stream from the foremost extremity of the carapace 

 below the frontal plate. It is therefore always held 

 stretched straight forward during the motion of the 

 branchial feet, whilst, as a rule, as soon as the 

 motion ceases, it is bent downwards, by which action 

 it, like a cover, closes the foremost aperture of the 

 carapace. 



Distribution. The species seems to have quite 

 an extraordinarily extensive geographical distribu- 

 tion. Besides on the Norwegian coasts, it is ob- 

 served in the Arctic seas, at Greenland, Spitzbergen 

 and Iceland; further, off the east coast of North 

 America, at the British Islands, and, as a whole, 

 along the entire North sea and Atlantic coasts of 

 Europe; and, it likewise occurs in the Mediter- 

 ranean, where it, in certain places, such as the (-i-ulf 

 of Naples, is not uncommon. 



2. Nebalia typlilops, G. 0. Sars. 



(PI. I, 13g. 4, PL IV, figs 9—19). 



Nehalia typhlops, G. O. .Sars, Nye Dyb\andscrustaceear fra Lo- 

 foten; Chr. Vid. Selsli. Forh. f. 1809. 



Specific Characters. Very like the preceding 

 species in its general habitus, although, perhaps, a 

 little more stumpy in sliape. Carapace, viewed 

 latei'ally, oval in form, a little lower in front, 

 and with the lower edges evenly curved at the 

 middle. Frontal plate well developed, oblongo-oval, 

 strongly arched above, and furnished at the extre- 

 mity with a pointed spiniform prominence. Eyes 

 extremely small and rudimentary, passing into co- 

 nical form at the end, and without trace of pig- 

 ment or visual elements. Superior antennæ (in 

 female) relatively shorter than in the preceding 

 species, with the flagellum scarcely longer than the 

 peduncle and only com])osed of 10 joints; the la- 

 melliform appendage rather prolonged, almost half 

 the length of the flagellum. Inferior antennæ 

 about as in N. hipes. Branchial feet with the 

 endopodite very slender and greatly prolonged. 



