906 Stimpson on the Crustacea and Echinodermata 
PORCELLIO GEMMULATUS. Dana. 
Porcellio gemmulatus, Dana; U. S. Exploring Expedition, Crust. ii. 725. 
Pl XLVII.f.7. Proc. Acad. Nat. Sci. Philad. vii. 176. 
Philoscia tuberculata, Srimpson; Proc. Cal. Acad. Nat. Sci. i. 89. 
This little wood-louse is somewhat variable in many of 
its characters. The dorsal granulation is coarser in some 
specimens than in others, and often shows no tendency to 
arrangement in rows. The spines of the feet of the second 
pair are simple in some specimens. A comparison of many 
individuals convinces me of the identity of my Philoscia 
tuberculata with the species previously described by Dana. 
Hab. Oregon, (Expl. Exped. ;) “ California,” (Le Conte ;) 
San Francisco, (Expl. Exped. and N. P. Exped.) 
Mus. Expl. Exped.; N. P. Exped. 
STYLONISCUS GRACILIS. Dana. 
Styloniscus gracilis, DANA ; Proc. Acad. Nat. Sci. Philad. vii. 176. 
Hab. California, (Le Conte.) 
Mus. of Prof. Dana. 
ALLONISCUS PERCONVEXUS. Dana. 
Alloniscus perconvexus, DANA ; Proc. Acad. Nat. Sci. Philad, vii. 176. 
Hab. California, (Le Conte.) 
JMus. of Prof. Dana. 
Both the above species, like the two preceding them, are 
terrestrial. 
LYGIA OCCIDENTALIS. Dana. 
Lygia occidentalis, Dana; U. S. Exploring Expedition, Crust. ii. 742. 
F XLIX. f. 7—Proc. Acad. Nat. Sci. Philad. vii. 176. 
The Lygie are isopoda of rather large size, and pe 
amphibious habits, generally found running about W: 
