508 



RemarJcs. — The present genus was established by Leach as earl\- as 

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

 regarded \>y Sp. Bate as identical with tlie genus Ceradocus of Costa. Some 

 species referred by Dana to the genus 3I(era 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 gemis 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, (jVIont.). 



(PI. 179). 



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



Syn. : Gammarus Dugesii, M-Edw. 



» — inasqvimanus, Sp. Bate. 



Body moderately slender and rather compressed, with the mesosome 

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

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

 each supplied at the base with a stifi bristle. Cephalon about the length of the fii'st 

 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 jiosteriorly, 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 bi'ownish. 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 tlie 2nd, flagellum somewhat longer than the peduncle, and c'omposed of 

 about 22 articulations, accessory appendage rather small, biarticulate 

 Inferior antennae much shorter tlian the superior, the last 2 joints of the 

 peduncle nearly equal-sized, flagellum scarcely longer than the last peduncular 

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

 bristles. Anterior gnathopoda ver}' small, with the propodos much shorter 



