23 



men skiller sig forøvrigt ikke sjmderligt i sin 

 Bygning. 



De 2 Par rudimentære Bagkropslemmer (Fig. 6 

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

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

 flodled, 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 Iios Hunnen meget paa- 

 faldende Længde, idet de endog er saa l^nge som 

 de 5 bagre Bagkropssegmenter tilsammen, eller næ- 

 sten af Legemets halve Længde. De er (Tab. IV, 

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

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

 kanten her er meget talrigere og finere end de i 

 Inderkanten. Desuden tindes, som hos Hunnen, langs 

 den indre Kant en Rad af temmelig lange og tynde 

 Fjærbørster. 



Farven er i levende Tilstand gjennemgaaende 

 blegere end hos Hunnen og Legemet halvt gjennem- 

 sigtigt. 



Indre Organer. 



Undersogelsen 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 Dyr, og ved Dissection 

 af opbevarede Exemplarer kommer man ikke meget 

 langt, paa Grund af det complieerede System af 

 Mu.skler, 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 Snitniethoden 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 

 Lidivider og undersoge disse directe under Mikro- 

 skopet i levende Tilstand. Ved at combinere disse 

 Undersogelser med livad 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 

 etterat disse Under.søgelser forlængst var afsluttede, 

 erholdt jeg Prof. Claus's fortjenstfulde Arbeide: 

 IJntersuchungen zur Erforsehung der genealogischen 

 Orundlage des Crustaceen-Systemv, hvori den indre 

 Organisation hos Nebalia i Korthed omtales, med 

 Vedføielse af stærkt forstørrede Fiij-urer af Han os 

 Hun, fremstillede som transparente Objecter. De 



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

 wise distinguish themselves particulai'ly in their 

 structure. 



The 2 paii's 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 

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

 to the length of the same in the female, as the}- 

 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 sei'ies of 

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

 edge are here miich more numerous and finer than 

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

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

 pretty long and thin pliimose setæ. 



The colour, in the live state, is, pe^vadingl3^ 

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

 transparent. 



Internal organs. 



The 

 is in the present animal 



investigations of the internal organization 



form attended with (juite 

 special difficulties. The animal is generally insuffi- 

 ciently transparent to enable ixs 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 veiy narrow, body- 

 cavity. To that is added still, a very strongi}- 

 developed, and with fatty globules filled, connective- 

 tissue, which encloses tlie various organs, and per- 

 mits itself with difficulty to be sepai-ated from 

 them. Neither has the sectional method afforded 

 me completely satisfactory results. I have been 

 enabled to investigate the internal structure in its 

 entirety best, 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 1 have been able to present by dissec- 

 tion, I have finally after much difficulty, 1 believe, 

 been able to obtain in some measure an elucidation 

 of the internal organization of this remarkable ani- 

 mal form. First after these investigations had long 

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

 admirable work Untersuchuugen zur Erfursehung 

 der genealogisciien Grundlage des Crustaceen Sy- 

 stem» in which tlie internal organization of Xebalia 

 is shortly mentioned, and illustrated by greatlv mag- 



