914 Dr. Lracn’s Arrangement of the Crustacea, $c. 
SUBDIVISIO l. 
* Styli caudales bini caule duplici, stipitis ar rticulive communis baseos 
apice inserto." Latr. 
Gen. 34. Licıa, Latr: 
Antenne externz articulo ultimo e pluribus aliis composito. 
Spec. 1. Ligia oceanica. 
L. antennis corporis longitudine, dorso subscabroso. 
Ligia oceanica. Fabr. Suppl. Ent. Syst. 301. 
Habitat ad littora maris; colore, magnitudine, et articulorum an- 
tennarum exteriorum numero valde varians. 
The illustrious Latreille, in describing the species of this genus, 
has considered the number of joints in the last segment of the 
antenne an unerring mark of specific distinction ; but we have 
‘found on examination that these parts are subject to great va- 
riety, not only in the same species, but even in the same indivi- 
dual, the antennz of the left side having two or three joints 
more or less than those of the right side. Other marks must — 
therefore be looked for; and probably sculpture or degree of 
roughness is that which will be found to distinguish the species. 
Ligia oceanica and L. Scopulorum of the Edinburgh Encyclope- 
dia are merely varieties of this species. 
SUBDIVISIO 2. 
Styli caudales quatuor, lateralibus biarticulatis. 
* Corpus in globum haud contractile. 
a. Antenne externe articulis octo. 
Gen. 35. Pnriroscia, Latr. 
Antenne extern; basi nude. Cauda corpore abrupté angustior. 
Spec. 1. 
