508 



Remarks. The present genus was established by Leach as early as 

 in the year 1814, to include the Gammarus palmattis of Montagu. It is 

 regarded by Sp. Bate as identical with the genus Ceradocus of Costa. Some 

 species referred by Dana to the genus Mara of Leach, ought also to be included 

 in the present genus. It is nearly allied to Gammarus, from which it is 

 chiefly distinguished by the small size of the eyes, and by the structure of 

 the gnathopoda. The genus comprises several species both from the northern 

 and southern hemispheres. To the fauna of Norway belong 4 species, to be 

 described below. 



14. Melita palmata, (Mont.). 



(PL 179). 

 Cancer gammarus palmatus, Montagu, Transact. Linn. Soc. Vol. VII, p. 69, PI. VI, fig. 4. 



Syn. : Gammarus Dugesii, M-Edw. 



> inseqvimanus, Sp. Bate. 



Body moderately slender and rather compressed, with the mesosome 



and metasome quite smooth; 1st segment of urosome produced dorsally to a 



compressed triangular projection, 2nd to 2 small juxtaposed dentiform processes, 



each supplied at the base with a stiff bristle. Cephalon about the length of the first 



2 segments of mesosome combined, lateral corners somewhat projecting and 



evenly rounded, having below them a small lobe (the postantennal corners) 



defined from the former by a short incision. Anterior pairs of coxal plates 



considerably deeper than the corresponding segments; 1st pair scarcely 



expanded distally ; 4th pair slightly emarginated posteriorly, the emargination 



being defined below by an angular projection; 6th pair in female having the 



anterior lobe continued below to a peculiar, spirally-contorted process, wanting 



in the male. Last pair of epimeral plates of metasome produced at the 



lateral corners to a short dentiform projection. Eyes very small, rounded, 



pigment dark brownish. Superior antennae exceeding half the length of the 



body, 1st joint of the peduncle scarcely as long as the 2nd, and armed on 



the posterior edge with 4 5 small spines, 3rd joint about half the length 



of the 2nd, flagellum somewhat longer than the peduncle, and composed of 



about 22 articulations, accessory appendage rather small, biarticulate 



Inferior antennas much shorter than the superior, the last 2 joints of the 



peduncle nearly equal-si/ed, nagellum scarcely longer than the last peduncular 



joint. Both pairs of antennas fringed on both edges with fascicles of slender 



bristles. Anterior gnathopoda very small, with the propodos much shorter 



