S74 Dr. Leach’s Arrangement of the Crustacea, ^ c. 
SUBDIVISIO 1. 
Styli caudales bini caule duplici, stipitis articulive communis haseos 
apice inserto.” Latr. 
Gen. 34. Ligia, Lair. 
Antenna externse articiilo ultimo e pluribus aliis composlto. 
Spec. 1. Ligia oceanica. 
L. antennis corporis longitudine, dorso subscabroso. 
Ligia oceanica. Fabr. Suppl. Ent. Syst. 301. 
Habitat ad littora maris; colore, magnitudine, et articuloruiii 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 
antennae 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 antennae 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 globurn hand contractile, 
a. Antenna externa articulis octo. 
Gen, So. Piiiloscia, Latr. 
Antenna externae basi nudae, Cauda corpore abrupt^ angustior. 
• Spec. 1. 
