23 



men skiller sig forøvrigt ikke synderligt i sin 

 Bygning. 



De 2 Par rudimentære Bagkropslemmer (Fig. 6 

 og 7) er ligeledes noget storre end bos Hunnen, og 

 sidste Par (Fig. 7) har her et tydeligt afsat lidet 

 Eodled, ligesom Iste Par. I sin Form og Bevæbning 

 stemmer iøvrigt begge Par temmelig noie overens 

 med samme hos Hunnen. 



Halegrenene udmærker sig (se Tab. I, Fig. 3) 

 ved en i Forhold til samme hos Hunnen meget paa- 

 faldende Længde, idet de endog er saa lange som 

 de 5 bagio Ecgk'''~ipspcg.>'neriter tilsammen, eller næ- 

 stenaf Legemets halve Længde. i!c er (Tab. IV, 

 Fig. 8), som hos Hunnen i hver Kant bevæoaede 

 med en Rad af korte Torner, hvoraf dog de i Yder- 

 kanten her er meget talrigere og finere end de i 

 Inderkanten. Desuden lindes, som hos Hunnen, langs 

 den indre Kant en Rad af temmelig lange og tynde 

 Fjærborster. 



Farven er i levende Tilstand gjennemgaaende 

 blegere end hos Hunnen og Legemet halvt gjennem- 

 sigtigt. 



Indre Organer. 



Undersøgelsen af den indre Organisation er hos 

 nærværende Dyreform forbunden med ganske sær- 

 lige Vanskeligheder. Dyret er ialmindelighed ikke 

 gjennemsigtigt nok til at at man kan umiddelbart stu- 

 dere denne paa det levende D}^', og ved Dissection 

 af opbevarede Exemplarer kommer man ikke meget 

 langt, paa (rrund af det complicerede System af 

 Muskler, som omgiver og tildels fylder den i og for 

 sig meget trange Kropshule. Hertil kommer endnu 

 et meget stærkt udviklet, og med talrige Fedtkugler 

 fyldt Bindevæv, som omspænder de forskjellige Or- 

 ganer og'- kun vanskeligt lader sig skille fra samme. 

 Heller ikke Snitmethoden har givet mig fuldt ud 

 tilfredsstillende Resultater. Bedst har jeg kunnet 

 faa undersøgt den indre Bygning i sin Helhed ved 

 ,af et stort Antal Exemplarer at udvælge enkelte 

 ualmindelig gjennemsigtige og helst ganske unge 

 Individer og undersøge disse directe imder Mikro- 

 skopet i levende Tilstand. Ved at combinere disse 

 - Undersogelser -med hvad jeg har kunnet fremstille 

 ved Dissection, har jeg endelig efter meget Besvær 

 troet at faa nogenlunde Rede paa den indre Orga- 

 nisation hos denne mærkelige Dyreform. Først 

 efterat disse Undersøgelser forlængst var afsluttede, 

 erholdt jeg Prof. Clauss fortjenstfulde Ai-beide: 

 ' Untersuchuugen zur Erforschung der genealogischen 

 Grundlage des Crustaceen-System>^ hvori den indre 

 Organisation hos Nebalia i Korthed omtales, med 

 Vedføielse af stærkt forstørrede Figurer af Han og 

 Hun, fremstillede som transparente Objecter. De 



than in the female (see Pl. I, fig. 3), but do not other- 

 wise distingiiish themselves particularly in their 

 structure. 



The 2 pairs of rudimentary, posterior append- 

 ages of the body (figs. 6 and 7) are likewise some- 

 what larger than in the female, and the last pair 

 (fig. 7) have here a distinctly defined, small basal 

 joint like the 1st pair. In their .shape and armature 

 both pairs correspond otherwise pretty exactly with 

 the same organs in the female. 



The caudal rami distinguish themselves (see 

 PI. I, fig. 3) by a very striking length. in relation 

 to the length of the same in the female, as they 

 are even as long as the 5 backmost segments of the 

 posterior body taken together, or nearly half the 

 length of the body. They are (PI. IV, fig. 8), as in 

 the female, armed on each edge with a series of 

 short spines, of which, however, those on the outer 

 edge are here much more numerous and finer than 

 those of the inner edge. Thore are found, besides, 

 as in the female, along the inmvr edge, a series of 

 pretty long and thin plumose setæi 



The colour, in the live state, i'^, pervadingly, 

 paler than in the female, and the body is semi- 

 transparent. 



Internal organs. 



The investigations of the internal organii.ation 

 is in the present animal, form attended with quite 

 special difficulties. The animal is generally insu'^fi- 

 ciently transparent to enable us to study it directly 

 in the living state; and on dissection of preserved 

 specimens we make no great progress on account of 

 the complicated muscular system which surrounds 

 and partly fills the, in itself very nari'ow, body- 

 cavity. To that is added still, a very strongly 

 developed, and with fatty globules filled, connective- 

 tissue, which encloses the various organs, and per- 

 mits itself with difficulty to be separated from 

 them. Neither has the sectional method afforded 

 me completely satisfactory results. I have been 

 enabled to investigate the internal structure in its 

 entirety be.st, by choosing from among a large 

 number of specimens some more than usually trans- 

 parent, and preferably quite young, individuals, and 

 by investigating these in the live state directly under 

 the microscope. By combining these investigations 

 with what I have been able to present by dissec- 

 tion, I have finally after much difficulty, I believe, 

 been able to obtain in some measure an elucidation 

 of the internal organization of this remarkable ani- 

 mal form. First after these inve.stigations had long 

 previously been concluded, did I obtain Prof. Claus's 

 admirable work «Untersuchungen zur Erforschung 

 der genealogischen Grundlage des Crustaceen Sy- 

 stem» in which the internal organization of Nebalia 

 is shortly mentioned, and illustrated by greatly mag- 



