528 



Occurrence. — This species is by no means rare off the coast of 

 Norway, being found in numerous places both on the south and west coasts 

 lip to the Trondhjemsfjord, in moderate depths. The colour, in the living 

 animal, is ver}- beautiful, and somewhat different from that in the other species. 



25. Cbeirocratus assimilis, (Lilljeborg). 



(PI. 186, fig. 2), 

 Gatnmarus assimilis. Lilljeborg. ©fvers. af Kgl. Svenska Vetensk. Acad. Forh. 1851, p. 23. 



Syn ; Cbeirocratus mantis, Norman. 



Body comparatively slender, resembling that in the last described 

 species, urosome armed in the usual manner. Cephalon about the length of 

 the first 2 segments of mesosome combined, lateral corners somewhat less 

 produced than in C. intermedius, postantennal ones, on the other hand, greatly 

 projecting and acuminate. Coxal plates about as in tliat species. Last pair 

 of epimeral plates of metasome produced at the lateral corners to a rather 

 short acute projection. Eyes somewhat larger than in C. intermedins, otherwise 

 of the usual appearance. Superior antennae not extending to the end of the 

 peduncle of the inferior ones, flagellum about the length of the peduncle. 

 Anterior gnathopoda with the propodos shorter than the carpus. Posterior 

 gnathopoda in male very much elongated, propodos rather large, gradually 

 widening distally, and clothed on both edges with fascicles of short bristles, 

 palm much shorter than the hind margin, and defined below by an acuminate 

 projection bearing at the base a slender spine, palmar edge scarcely setous, 

 but divided into 3 dentiform projections, the anterior of which is rather 

 prominent, and minittely trilobate at the tip, dactylus extremely strong, 

 expanded in the middle and falciform, impinging when closed against the 

 projection defining the palm below. Posterior pairs of pereiopoda in male 

 rather strongly built, last pair much longer than the preceding pairs, and 

 having the joints broad and compressed. Last pair of uropoda exceeding in 

 length the urosome, rami rather broad and twice as long as the basal part, 

 being edged with slender spines. Telson much broader than it is long, cleft 

 rather wide, terminal lol)es comparatively broad, and each armed at the tip 

 with only 3 spines, the second of which is somewhat longer than the 

 other 2. Body pale yellow, mottled with small red spots. Length of 

 adult male reaching 13 mm. 



Itemarlis. — This form was first described by Prof. Lilljeborg as 

 Gammarua assimilis, on account of its near relationship to Gammarus Sunde- 



