the Trondhjem Fiord. 34:5 



The Crustacea of the Norwegian fiords possess a peculiar 

 interest when compared with British and Arctic species. As 

 we go further and further north the Brachyura and Anoniura 

 gradually decrease in number, and species after species drops 

 out. To make up for their absence there is a much larger 

 development of Cumacea, Mjsidea, and Amphipoda on the 

 Norwegian coast, while in the true arctic seas the Ampliipoda 

 attain their maximum development — not, as far as jet known, 

 perhaps in number of species, but in size and multitude of 

 specimens. The following list will give evidence of this 

 gradual suppression of Brachjura and Anomura : — 



Bracliyui"a. Anomuraf. 



Mediterranean * .... 79 23 



Britain 49 15 



Norway 24 9 



Greenland, Spitsbergen, and Kara Sea . . o 2 



Of the three Arctic Brachjura the great Chionrecetes pha- 

 langmm is a trulj arctic form, circumpolar in its distribution. 

 ■ It often measures 2^ feet in stretch of legs. It rarelj occurs 

 outside the Arctic Circle, but on the American coast has been 

 found as far south as Casco Bay [S. I. Smith). On the 

 coast of Europe it is unknown. Hyas araneus and coarctatus 

 grow to an immense size in Greenland, but occur southwards 

 to the south coast of England in greatlj dwarfed dimensions. 

 The two Anomura, Lithodes arctica and Etipagurus pubescenSj 

 also reach England. If we deduct these four species it is 

 very remarkable that of the remaining twenty-nine species of 

 Norwegian Brachyura and Anomura there is only one, and 

 that of very small size, Eiqyagurus chiroacanthus^ Lillj., which 

 is not as yet known in the Mediterranean. Corresponding to 

 the decrease in the number of higher Crustacea as we go 

 northwards is the similar falling off in numbers as we descend 

 to greater depths in the sea J. Macrura, on the other hand, 

 are not unequally distributed, but seem to occur in no great 

 disparity of numbers in arctic, temperate, and warmer waters 

 and in the great depths of the ocean. 



The most marked peculiarity of the Norwegian fiords with 

 respect to the class Crustacea is the abundance of Mysidea 

 and Cumacea. In the month on tiie Trondhjem Fiord I 

 obtained more specimens of this tribe tlian I have found 



• I have not counted a ^reat many doubtful species recorded from tlie 

 Mediterranean in Carus, ' Faunre Medit. I'rodrnmus.' 



t I have not hero included tlie family (xalatbt'ldje in the Anomura. 

 No species of that family i?* found in the Arctic regions. 



J See Norman, " Presidential Address,'' Trans. N it. Hist. Soc. and 

 Tynes. Nat. Field Club, vol. viii. (LSSOj, p. laS. 



