95 



afrundede Endeled er meget redneerede i Antal. Epi- 

 poditen er overniaade liden og rndimeiitær, hvoriinod 

 Exopdditen er forholdsvis vel udviklet, iiaaeiide med 

 sin ventrale Lap langt \\d over Endopoditen. Den 

 er kantet med omtrent '2'å l>orster af noget nlige 

 Længde. Meget lignende, skjondt endnu noget sim- 

 plere, er Bygningen af det 24de Par hos meget store 

 Exemj)larer, saaledes som dette er beskrevet og af- 

 bildet af Prof. Lilljeborg. 



Legemets Farve er hos fuldvosne Exemplarer 

 mere eller mindre tvdelig olivengren, gaaende paa 

 Bngsiden og paa Fodderne over til gnlrodt. Selve 

 Skallen er lyst hornfarvet og temmelig gjennem- 

 sigtig, dog meget constant med Dorsalkanten af en 

 ret ioinefaldende mork graasort Farve. 



ludrc Organer. 



Paa Griind af denne Forms store (Trjennem.sigtig- 

 hed, vil den indre Organisation ret vel kunne stu- 

 deres, navnlig paa levende Exemplarer, tildeLs ogsaa 

 paa vel jireserverede Spiritusexemplarer, \;den at 

 nogen Dissection strengt tåget er fornøden. Kun 

 hvor det gjælder en mere detailleret (histologisk) 

 LTndersogelse af Organerne, vil det være nj'ttigt at 

 .skride til en Sonderlemmelse af Dyret. 



Med den sædvanlige Indleirings- og Snitmethode 

 kommer man ikke synderlig vidt, og denne i vor 

 Tid i saa stor Udstrækning anvendte Undersogelses- 

 methode synes idethele at være lidet anvendelig, 

 hviir det gjælder Krebsdyr. 



Fordøielsesapparat. — Tarmen strækker sig som 

 et nogenlunde jevnt tykt Ror gjennem hele D}Tets 

 Legeme, og skinner meget tydeligt igjennem Inte- 

 gumenterne ved dens sædvanligvis morke Contenta 

 (se Tab. XV, Fig. 1). Den ender i Halen med en 

 kort, stærkt muskuløs Endetarm, som udmunder paa 

 Halens Spids, mellem Haleklørne. I Xakkesegmentet 

 gjor Tarmen en pludselig, næsten vinkelformig Bei- 

 ning nedad, i Overensstemmelse med Legemets stærke 

 Krumning paa dette Sted. Tarmens Indhold er i 

 denne forreste Del sædvanligvis lysere, orangefarvet 

 eller blegt gulagtigt. Sjiiseroret er ganske kort og 

 passerer fra Mundaabningen lige fortil, hvor det 

 munder i Tarmens forreste Ende med en i dens 

 Liimen fremspringende noget udvidet Del (se Fig. 9, 

 oes). I Forbindelse med Tarmen staar et temmelig 

 voluminøst og ronipliceret kjertelagtigt Organ (Fig. 

 2, 3, /), der ndfvlder en stor Del af Hovedets indre 

 Hirle, og aabenbart svarer til den hos Lepidtirns 

 ligeledes i Hovedet beliggende Lever. Ligesom hos 

 Lepidurus, bestaar (;)rganet af 2 symetriske Halv- 



from the others. It is very small, and its endopo- 

 dite is (|uite short, with only 3 lobes inside in addi- 

 tion to the coxal lobe. The bristles on these lobes, 

 as also on the short rounded terminal joint, are 

 greatly reduced in number. The epi^odite is excee- 

 dingly snuill and rudimentary, Avhereas the exopo- 

 dite is comparatively well developed, reaching far 

 out over the endojiodite with its ventral lobe. It 

 is edged with about 23 bristles of somewhat unei[ual 

 length. The structure of the 24th pair found in 

 very large specimens, though rather more sim[)Ie, 

 is very similar, as described and figured by Prot. 

 Lilljeborg. 



The colour of the body in full-grown s]3ecimens 

 is more or less distinctly olive-green, merging into 

 yellowish red on the ventral side and on the leg.s. 

 The shell itself is of a light horn-colour, and toler- 

 ably transparent, though the dorsal margin is 

 almost invariably of a very conspicuously dark 

 grey coloxir. 



luterual Organs. 



On account of the great transjiarency of this 

 form, its internal organisation may be very easily 

 studied, especially in living s])ecimens, to a certain 

 extent too, in well-preserved spirit specimens, with- 

 out the necessity of dissection. •)nly when a more 

 minute (histological) investigation of the organs is 

 to be made, will it be useful to resort to a dismem- 

 bering of the animal. 



B^f the ordinary imbedding and section method, 

 not much information is to be gained, and this mode 

 of investigation, now so widely employed, seems, 

 on the whole, to be of very little use as regard.? 

 Crustaceans. 



Digestive System. — The intestine runs, in the 

 form of a tube of fairly even thickness, through the 

 whole body of the animal, and i.s very distinctly 

 seen through the integuments by reason of its gene- 

 rally dark contents (see PI. XV, fig. 1). It termi- 

 nates in the tail in a short, very muscular rectum, 

 which opens out at the ]joint of the tail, between 

 the caudal claws. In the cervical segment, the inte- 

 stine makes a sudden, almost angular bend down- 

 wards, following the sharp curve of the body at 

 that jilace. The contents of the intestine in this 

 foremost part are generally lighter, of an orange 

 or pale yellow Irae. The æsophagus is quite short 

 anil passes from tlie oral aperture straight for- 

 wards, where it opens into the anterior end of the 

 intestine by a somewhat expanded part projecting 

 into its lumen (see fig. 0, oes). In connection with 

 the intestine, there is a rather voluminous and 

 complicated glandular organ (figs. 2, 3, /) occupj-ing 

 a great part of the inner cavity of the head, and 

 evidently answering to the liver in Lepkluru^. whidi 



