21f> AJtrniroDA norm alia. 



This species exists jijenerally in a band ronnd the coast somewhat 

 nearer the sliore than G. Locusfa. I have frequently taken it with 

 quantities of a species of Vorticella attached to the three anterior 

 pairs of pkmpoda. 



llatlike's descriptions of G . poecUurus and G.Kroi/eri agree precisely 

 with Milne-Edwards's description of G. Olivii ; but, in his figures, 

 the palm is drawn as serrated in G. poecilurns, but not in G. Kroyeri -. 

 this character not being noticed in the text by Rathke, and Lilje- 

 borg and Bruzelius having united G. Kroi/eri with G. poecilurus, 

 induce me to believe that the serrated character of the palm in 

 poecilurus is an error of the artist. 



20. Gammarus Ochotensis. (Plate XXXYIII. fig. 5.) 

 Ganimarus Ochotensis, Brandt, Sibirische Reise, Zool. i. pi. 6. f. 31. 



First tkree segments of the pleon having several small spines on 

 the posterior dorsal portion ; foiu'th having an upright longitudinal 

 plate crowned with small spines on each side of the central dorsal 

 line ; fifth and sixth crowned with spines. Eyes small, ovate. 

 Superior antennfe longer than the inferior. Inferior antennae 

 having the peduncle longer than the peduncle of the superior. 

 Gnathopoda subequal ; propoda ovate, palmte oblique. Third pair 

 of perciopoda shorter than the second and fourth. Posterior pair 

 of pleopoda long, rami unequal ; inner ramus rudimentary, outer 

 very long, and furnished with short haii-s. 



Length 1 inch. 



Hah. Ochotsk Bay {Mkldendorff). 



21. Gammarus Arcticus. (Plate XXXVIII. fig. 6.) B.M. 



Gammarus arcticus (young), Leach, 3IS., Uliite, Cat, Crusts B. M, 

 1847. 



Eyes round, small. Superior antennae about half the length of the 

 animal ; flagellum rather longer than the peduncle ; secondary 

 appendage uniarticulate. Gnathopoda short, robust: first pair 

 rather stouter than the second ; carpus as long as the propodos ; 

 propodos subovate, palm imperfectly defined by two short spines, 

 marginate, margination narro-\ving towards the inferior angle, 

 the edge notched at short distances : second pair* having the 

 propodos longer than the carpus, long-ovate ; pahu not oblique, 

 rounded at the inferior angle, and imperfectly defined ; dactylos 

 shorter than the palm. Posterior pair of pleopoda having the 

 rami unequal, the inner ramus being scarcely half the length of 

 the outer. 



Length g^ths of an inch. 



Hah. Baffin's Bay. 



