12 



Id-lit in against the former. Third pair of pereiopoda greatly produced and 

 generally much longer than the 2 succeeding pairs, having the carpal and 

 propodal joints very elongated and the latter often peculiarly denticulated, 

 whereas the meral joint is much abbreviated. Uropoda rather slender. Telson 

 small, triangular. 



RciHdi-kx. As mentioned above, this genus is very nearly related 

 to the preceding one, scarcely differing except in the mutual longitudinal 

 relation of the pereiopoda and in the powerful structure of the 2 anterior pairs. 

 The usual known generic denomination, TJirmixto, has been changed by 

 Dr. Bovallins to Entlmuisto, because the former name was employed in 

 Zoology anterior to 1828. The genus is represented both in the antarctic 

 and arctic Oceans. Dr. Bovallius enumerates G species, one of which, however 

 E. Nordnixl-jitldi Bovall., has been withdrawn by Dr. Hansen as most probably 

 only founded on immature specimens of E. lilx'llula. (Mandt). No less than 3 

 different species belong to the Norwegian fauna. 



5. Euthemisto compressa, (does). 



(PI. 5, fig. 2). 



Themisto compressa, Goes, 0fvers. af Kgl. Svenska Vetensk. Akad. forhaudl 1865, 



p. 533, pi. 41, fig 34. 

 Syn : '? Enthenmto bispinosa, Bovall., not Boeck. 



Body moderately slender and highly compressed, back distinctly 

 carinated and forming on the posterior segments of the mesosome and the 

 anterior ones of the metasome sharp recurved processes. Cephalon, as seen 

 laterally, rounded triangular, more deep than long; eye-pigment of moderate size, 

 oval. Superior antennae in female about the length of the cephalon, nagellum 

 strongly curved and denticulated on the posterior edge. Posterior gnathopoda 

 with the carpal process almost reaching "the tip of the propodal joint, dactylus 

 scarcely more than half the length of the latter joint. Carpal joint of the 

 2 anterior pairs of pereiopoda regularly oval, broadest in the middle, with 

 rather short and unequal bristles on the posterior edge. Third pair of pereio- 

 poda only slightly exceeding in length the 2 succeding ones, basal joint not 

 expanded, propodal joint very slender and about the length of the 3 preceding 

 joints combined, anterior edge very minutely denticulated throughout and 

 provided at regular intervals with about 10 slender bristles; dactylus rather 

 elongate, unarmed. Posterior pair of uropoda nearly twice the length of the 

 urosome, outer ramns much shorter than inner. Body pellucid, with dark 

 inti-sline and scattered purplish pigmentary spots on the posterior division 

 of Ihc body. Usual length 12 mm. Maximum length of arctic specimens, 

 according to Bovallius, 30 mm. (?). 



