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Norwegian Aniplii])oda was still restricted to Boeck's work, tbe use of wliieli 

 was, as above stated, connected with veiy much difficulty. Under such 

 circumstances, I thought it right in the first instance to enter upon a tulal 

 revision of this order, hoping tiiereby to supply the above-mentioned wants 

 in Boeck's work. To this end, T have gone over the vast collection of Amphi- 

 poda made by Boeck, and especially most carefully examined the several type 

 specimens in the collection, whereby several difficult questions about the right 

 identification of the Boeckian species have been finally settled. Nearly all 

 the species described in the said work have been subsequently found by myself, 

 and in most cases examined in the living state, and numerous additional 

 species have been procured, increasing the number of Norwegian forms to 

 about 400 in all. 



The aim of the present Volume is chiefly to facilitate the determina- 

 tion of the northern Amphipoda. This, I believe, may be best attained, not 

 only by giving good and concise diagnoses of the species, but especially by 

 supplying figures, true to nature, and of sufficient size and clearness, both of 

 the entire animal and of the most characteristic anatomical details. The lack of 

 good figures has indeed hitherto made the study of this interesting order of 

 Crustacea very difficult and, in many cases, has caused sad confusion ir 

 the synonymy. Very great rare has therefore been paid to the preparatioT 

 of the plates accompanying this Volume. They have been all drawn by the 

 author himself, by the authographic method applied by him very successful'. -5 

 during a series of 3'ears, and the habitus-figures have, in nearly every case 

 been copied from carefully executed, coloured drawings made by the author 

 from living specimens, thus showing the mode of pigmentation characteristic 

 to each species. In every generic type the structure of the oral parts has 

 been carefully examined, and figures of the same given on a greatly enlarged 

 scale, as the classification of the Ami)hipoda ought chiefly to be based upon 

 this character. 



As to the systematical arrangement of the Amphipoda, I have on]y 

 made some few changes in the system adopted by Boeck. It is, however, niost 

 probable, that a somewhat altered arrangement may be found convenient 

 in future, as some of the families are far from being well defined. 



In the Appendix to the volume some additions and corrections have 

 been given, and some new species described and figured. 



During the elaboration of the work, I have had very important 

 assistance in the excellent Report of the « Challenger* Amphipoda by the Rev. 

 Mr. Stebbing the very complete and elaborated survey of the literature given 

 in that Report having especially been most invaluable to me. 



I regret not having had an opportunity of consulting the recently 



