﻿CRI'STACICA .MALACOSTRACA. 



Nevertheless, I am myself guilt\- here of publisliiiio; a fannistic list. It would, however, be 

 meaningless to give new descriptions of the species (with figures) of all tlie n(jrthern-arctic Decapoda, 

 most of which have been described several or even man\- times, and for example to describe and 

 figure the Cumacea, Isopoda and Amphipoda which have been so excellently dealt with in Sars' standard 

 work mentioned above. But wherever on going through nu- large material I have met with a note- 

 worthy difference between my specimens and the work noted by me as the chief publication regarding 

 the species in question, I have dispia\'ed the differences discovered by notes and often likewise b\- 

 figures, so that a possible error of determination may be controlled b\- a successor, who in one or 

 other regard has better material or more critical ability. With this object in view I ha\-e marked 

 with ! the work or the two works for each species which contain the best description of the form; 

 also, under remarks I have sometimes briefly mentioned one or several of the principal specific 

 characteristics. I have thus done what I could to give the users of this work the greatest possible 

 control as regards my own determinations, and hope further that these measures of circumspection 

 may be a good example to others who in future wish to publish fannistic catalogues of Crustacea. 



With regard to species which have been described several or many times it has seldom been 

 my intention to refer to all the pre\-ious descriptions and figures in the synonymy list. I only give 

 a greater or less selection which always contains the first description and the one or two best (marked 

 as mentioned above). In the synonymy list u o reference is e\'er given to mere lists of names, and 

 reference is only made to a work if it contains either a description or a figure or at least remarks of 

 importance for the recognition of the species. I may add, that I have always used the works cited 

 under each species, except in the cases where these were not available and then I mention the source 

 of my citation. It is very common to find that authors give citations of descri])tions of a species and 

 of localities, where these are only mentioned in the same way, so that one cannot see whether there 

 is in the work cited only a name and some localities or likewise a description; in this way the 

 synon\-my list sw^ells up to an unreasonable extent and at the same time becomes not nearly so 

 reliable or so useful as a list much shorter but carefully chosen. Another and not ver\- rare bad 

 habit is that an author, in a synonymy list for example, cites a treatise he either does not know or 

 has not looked at in the case in question, but has copied it from another's list; it happens that such 

 slackness can be detected, when the author in his citation includes the written or printed error found 

 in the citation of his predecessor by a third person. Under occurrence and distribution I have 

 generally given for each locality or small group of localities the author or the authors as the source of 

 information but not mentioned the works; and except where the contrary is stated I have everywhere 

 examined the source myself. It is only when I have studied specimens from the same coast that I 

 omit frequently any reference to earlier notices; where therefore no author is named for a locality or 

 for several localities mentioned immediately after one another, that means that our i\Iuseum owns the 

 species in question from these localities. 



For a large number of the earlier described species I have gi\-cn the length — sometimes also 

 other measurements — of the largest specimen seen by me, as also the place where it was taken; in 

 several cases these sizes are greater than those hitherto known for the species in question. For some 



