JEGA PSORA, 283 
ISOPODA. LEGIDA. 
NORMALIA. 

fEGA PSORA. 
Specific character. Oval and convex, cox marked with two oblique lines ; 
those attached to the four anterior segments square, those to the three poste- 
rior segments subtriangular and distant from each other; terminal segment 
of the pleon triangular, smooth on its upper side, with the lateral margin 
slightly dilated ; inner plate of the lateral appendages emarginate near the 
extremity of its outer edge. 
Length, 1} to nearly 2 inches, 
Oniscus psora. Pennant, Brit. Zool. vol. iv., pl. 18, f. 1, 1777 (certe). 
diga emarginata. Leacu, Dictionn. Sci. Nat. xii. p. 349. Trans. Linn. 
Soc. xi. p. 370. Suppl. Enc. Brit. 1, 428, pl. 22. 
SaMOUELLE, Ent. Compend. p. 109. DrsmAxzst, 
Crust. p. 305, pl. 47, f. 4, 5. Mine Epwarps, 
. Crust. iii., p. 240. Cuvier, Régne An, (Ed. Crochard), 
Crust. pl. 67, f. 1. 
Tuis species is distinguished at once by the somewhat 
triangular form of the terminal segment of the tail, which 
