Ved Bearbeidelsen af det særdeles vidtloftige Materiale 

 af Crustaceer, indsamlede og iagttagne under Expedi- 

 tionen. har jeg fundet det praktisk rigtigt at dele min Af- 

 handling i tre Afsnit. I 2det Afsnit gives en fuldstændig 

 systematisk Fortegnelse over samtlige under Expeditionen 

 iagttagne Arter med Angivelse at' Findested samt korte 

 Bemerkninger om Forekomst og Udbredning. I sidste Af- 

 snit meddeles de mere almindelige Slutninger, hvortil Studiet 

 af Nordhavsexpeditionens Crustaceer har ledet, dels i Hen- 

 seende til Faunaens almindelige Character, dels til dens 

 supponerede Bevægelse (Ind- og Udvandring af Dyreformer) 

 samt de physiske og meteorologiske Forhold, som herved 

 synes at være bestemmende. Forste Afsnit er derimod kun 

 forbeholdt udforlige Beskrivelser af nogle enkelte Former, 

 der enten er nye for Videnskaben eller hidtil mindre fuld- 

 stændigt beskrevne og afbildede. Herved er dog at mærke. 

 at jeg ialmindelighed ikke har indbefattet herunder de 

 Former, som tidligere er constaterede som tilhørende Norges 

 Kystfauna. Disse sidste vil paa et andet Sted blive ud- 

 førligt omhandlede, nemlig i et storre faunistisk Arbeide 

 over Norges Crustaceer, som jeg med det allerforste agter 

 at paabegynde. 



Til de medfolgende Plancher har jeg selv udfort alle 

 Figurer og overalt herved anvendt Camera lucida. hvorved 

 deres Nojagtighed er garanteret. Til Grand for de fleste 

 Habitusfigurer ligger colorerede Tegninger udforte af mig 

 under selve Expeditionen efter friskt indfangede og endnu 

 levende Exemplarer. 



De her beskrevne nye Former er tidligere .kortelig 

 blevne characteriserede i følgende to paa Latin affattede 

 foreløbige Afhandlinger, begge indførte i "Archiv for Mathe- 

 matik og Naturvidenskab" : 



1. Prodromus descriptionis Crustaceorum et Pycnogo- 

 nidarwm, gvæ in Expeditimn' Xmregica anno 1876 observavit 

 G. 0. Sårs. 



2. < 'rustacea et Pycnogonida noia in itinere 2do et 

 3tio Eocpeditionis Norregicæ anno 1877 & 1878 coUecta. 

 (Prodromus descriptionis). 



For at undgaa Gjentagelser ved Opgivelsen af Finde- 

 stederne. meddeles nedenfor en Tabel over alle de Stationer, 

 paa hvilke Bundskrabe eller Trawl har været anvendt, med 

 Den norske Nordhavaexpedition. G. O. Sårs Crustacea. 



In working up the verv extensive material embracing the 

 Crustaceans collected and observed on the Norwegian 

 North-Atlantic Expedition. practical reasons have induced 

 me to divide mv Memoir into three sections. The second 

 section gives a complete systematic enumeration of the species 

 observed on the Expedition, as also a statement of the localities 

 vhere found, together with brief remarks on occurrence and 

 distribution. In the third section are set forth the chict 

 conclusions to which a study of the Crustacea from the 

 North-Atlantic Expedition has led. partlv in regard to the 

 genera] character of the Fauna, and partlv with reference 

 to its supposed movements (migration oi animal forms), as 

 also to the physical and meteorological conditions which 

 appear to determine the occurrence of species. The first 

 section has been devoted exclusively to detailed descriptions 

 ul certain forms either new to science or which. up to the 

 present time, have been incompletelv diagnosticated and 

 figured. Meanwhile. I must not fail to observe. that as a 

 rule I have not included forms previously established as 

 belonging to the Norwegian littoral fauna. Such forms will 

 be fully treated of elsewhere, viz. in a work on the Cru- 

 stacea of Norway, which I purpose beginning at an early 

 date. 



For the Plates accompanying tliis Memoir. all of the 

 figures were furnished liv myself; and the use, without e.\- 

 ception, of the Camera Lucida affords a sufficient guarantee 

 for their accuracy. Most of the habitus-representatious 

 are facsimiles of coloured drawings. executed by myself on 

 the several cruises of the Expedition, from fresh and living 

 specimens. 



The new forms described in the first section of this 

 Memoir are briefly characterized in the two following preli- 

 minary papers, both published in «Archiv lur Mathematik 

 og Naturvidenskab": — 



1. — Prodromus descriptionis ('rustan om w et Pycno- 

 gonidarmn. qiv in Expeditione Norvegica anno 1876 obser- 

 vavit 0. 0. Sårs. 



2. — Crustacea et Pycnogonida nova in Hinere 2do 

 et 3tio Expeditionis Norvegicas anno 1877 & 1878 coUecta 

 (Prodromus descriptionis). 



To a vi ml repetition in stating the localities. I have 

 given below a List of all the Stations at which the dredge 

 or the trawl was used. along with the date. position of the 



1 



