10 



Gen. 3. ParathemistO, Boeck, 1870. 



Body somewhat compressed, Init with tlie back scarcely cariiiated. 

 Ceplialuii iiTeg-uUuiy rounded; mesosome moderately vaulted; metasorae well 

 developed, with large epimeral plates. Antennae in female subequal, more 

 elongated than in tlie ])receding genera; in male about as in Hy]ieria. 

 Anterior lip with a large uneciually bilobed buccal plate ; posterior liji with the 

 lobes densely ciliated, lateral corners produced. Mandibles rather strong, 

 cutting edge very In'oad and minutely denticulated, molar exjmnsion rather 

 large, regularly serrate on the edge, palp witli the middle joint very elongated. 

 First pair of maxilke witli the ]>alp rather expanded, inner edge denticulated 

 and terminating with a small tooth-like ])i'ojection. Terminal lobes of the 

 maxillipeds aciiminated and beset with scattered long setae. Grnathopoda 

 densely hirsiate and rather dissimilar; 1st pair simple, with the carpal joint 

 rather l)road and iu»t produced interiorly; 2nd pair subchelate, the carpal 

 joint being produced to a narrow process, which does not, however, reach the 

 end of the jDropodal .joint; dactylus of both pairs rather elongated. The 2 

 anterior pairs of ' pereiopoda having the carpal joint only slightly dilated; the 

 3 posterior pairs very slender, sube([ual, with the carjml and propodal joints, 

 especially the lattei', greatly elongated and almost naked. Uropoda more 

 slender than in the preceiling genera. Telson comparatively small. 



lirmurk)<. — This genus, established by Boeck, is very nearly related 

 to the succeeding one, Euthemisfo, and ought perhaps to be combined with it. 

 The distinctive characters are chiefly the equal-sized antennae of the female, the 

 less powerful structure of the 2 anterior pairs of ])ereio])oda and the uiiitnrin 

 develo])ment of the 3 pcfsterior ones. Besides the northern sjiecies described 

 below, the Hijpi;ria frif/oiia of Dana would seem to belong to this genus, as also 2 

 new species described, the one by Bovallius, the other by the Rev. Stebbing. 



4 ParathemistO oblivia, (Kroyer). 



(PI 5, fig 1). 



Hyj/criii ohlivid, Kroyer, Gronlands Ainphipoder, 1 c. p. 70, pi. 4, fii;. 10. 



Syn: ParathemistO abynsorunt, Boeck. 



Body modei'ately slender, with the 1st segment of the mesosome 

 much longer tlian the 2nd. Ce])halon ratlier large, only sliglitly more deep than 

 long; eye-pigment oval, very darlc. Sujierior antennae in female alxnit as hnig 

 as the cejjhabin and the 1st segment of the mesosome conibiiieil, tlagelluin onl\- 

 very slightly curved, about three times the length of the jjeduncle. Gnatho- 

 poda with the propodal joint about as long as the carjial one; car])al ]n'ocess 

 "f 2ud pair very iinrrow, reaching beyond the middle of the propodal joint; 



