500 



iiropoda with the inner ramus well developed, reaching about to the end of 

 the 1st joint of the outer, and edged with numerous ciliated setse in addition 

 to the spines. Telson comparatively larger than in G. marinus. projecting 

 somewhat beyond the basal part of the last pair of uropoda, each half having 

 near the base a group of 3 unequal spines, and close to the tip another ver}' 

 small spimile, the apical spines being, as in the preceding species 3 in 

 number. Colour somewhat variable, being in female more or less dark 

 brownish green, with a very conspicuous pinkish patch, on each .side, at the 

 origin of the pleopoda; in male generally considerably lighter, yellowish brown. 

 Length of adult female 18 mm, that of male generally considerably greater, 

 amounting to 20 mm. Maximum length of arctic specimens 48 mm. 



RemarJcs. — There cannot be any doubt that the Cancer locitsta of 

 Linne is this species. Arctic specimens attain a much larger size than those 

 found farther south, and have therefore often been referred to separate species, 

 differently named by different authors, such as G. boreas, sitchensis, muintus. A 

 closer examination will however prove, tliat all these forms belong, in fact, 

 to one and the same species, that first named by Linne as above. It is 

 easily distinguished from the preceding species by the rather different form 

 of the lateral corners of the cepalon, tlie distinct nodular dorsal projections 

 of the urosome, the much broader e3'es, the rather different shape of the 

 gnathopoda in the two sexes, the more slender pereiopoda, and finally, by the 

 structure of the last pair of uropoda and that of the telson. 



Occurrence- — Along the whole coast of Norway this species is 

 rather frequently met with in the littoral and sublittoral regions. It 

 also occasionally descends to greater depths, at least to 50 fathoms, and 

 in some places occurs in great abundance among deca3dng algae, accumulated 

 on the bottom. Off the coast of J'^inmark it is often found considerably 

 above low water mark, beneath stones and pebbles. 



Distribution. — Arctic Ocean, widely distributed: Grreenland, Iceland, 

 Spitsbergen, Franz Joseph's Land, the Kara Sea, the Siberian Polar Sea, 

 Labrador; Atlantic coast of Europe, the Mediterranean, the Black Sea(?j- 



10. Gammarus campylops, Leach. 



(PI. no, fig. 2). 



Gammarus camoylojis, Leach, Liun. Transact. XL p. 360. 



Very like the preceding species, but much smaller, and also some- 

 what less slender in form. Cephalon fully as long as the first 2 segments 



