PORCELLIO, 473 
ISOPODA. ONISCID. 
NORMALIA, 
Genus—PORCELLIO. (Latreille.) 
Generic character. Ovate, sub-depressed. Cephalon with 
large lateral lobes. Outer antenns seven-jointed. Coxse of 
the second and sixth segments of pleon obsolete. Terminal 
uropoda with the basal portion triangular, flattened. Apical 
portion compressed, trigonate, exserted. Inner appendage small, 
curved, and trigonate, concealed by the last segment of the 
pleon, which is more or less concave on its upper surface. 
THE animals of this genus differ from those of 
Armadillo (which they resemble in having only seven- 
jointed outer antenna), in the form of the second 
joint of those organs, which is not furnished with 
a rounded lobe on the outside at its extremity—a 
peculiarity dependent on the different arrangement of 
the front part of the head, and the consequent manner 
in which these organs are disposed when at rest, the 
remarkable groove at the sides of the front of the head 
being here wanting. The late Professor Kinahan thus 
described the structure of the front of the head in 
Porcellio :— 
“External angles of the third antennary segment of 
the head more developed than in Oniseus, the superior 
margin raised into a lobe, which projects above the 
frontal line of the cephalic segment, and gives the head 
a trilobed appearance. This lobe, though sometimes 
badly marked (Porcellio pruinosus, Br.—P. frontalis Lereb., 
not Edw., for example), is present in all the species I 
: = leagues 
have had an opportunity of examining. 
