986 



CRUSTACEA. 



and when so situated, the projecting process (thumb-like) of the ante- 

 penultimate joint is not seen. 



Genus HYPERIA, LatreiUe. 



The Hyperise occur principally in the colder temperate and frigid 

 zones. The species have usually a tumid cephalothorax, rounded 

 above ; but, in one species, it is much compressed, and rises above to 

 an edge. The four anterior thoracic legs are much shorter than in 

 the others, and the second pair with usually the first, is subprehensile. 

 This prehensile character is produced by a prolongation of the lower 

 apex of the fourth joint, the fifth and sixth constituting the moveable 

 finger. This finger, exclusive of the claw, or sixth joint, is commonly 

 much longer than the process against which it j>lays ; yet the transi- 

 tion appears to be so gradual to species in which the finger is short, 

 and the hand well formed, that we have doubted the propriety of sus- 

 taining the genus Metoecus, of Kroyer, based on this distinction, — that 

 is, on having well-formed hands terminating the second pair of feet. 

 In our Hyperia trigona, the legs of the first pair are not at all prehen- 

 sile, the lower apex of the fourth joint not projecting. 



Hyperia agilis. 



Caput mediocre, pigmentis oculorwn angustis. Tlwrax longus, epimeris 

 totis brevibus, truncatis. Antennae, longiusculce, dimidii thoracis longi- 

 tudine, subasqum; 2dce parce longiores, 3-articulatQ3, non teretes, arttr 

 culo ultimo longo et remote" pubescente, interdum obsolete articulato; 

 lmce b-articulatce, articulo 4fo crasso longoque et infra ciliato, uUinv) 

 minuto. Pedes 4 antici sulxequi, coxis angiitis; 6 postici mediocres, 

 setis brevibus et paucis. 



Head of moderate size, pigment of eyes much smaller than usual. 

 Thorax long, all the epimerals short, truncate. Antennas rather 

 long (half as long as thorax), subequal; inferior slightly the longest, 

 three-jointed, not terete, last joint long, and remotely hairy ; supe- 

 rior five-jointed, fourth joint stout, long, ciliate below, the last 

 minute. Four anterior feet subequal, coxaa narrow; six posterior 

 of moderate length, setae short and few. 



