506 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, Stimpson; Proc. Cal. Acad. Nat. Set. 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.) 

 Mus. of Prof. Dana. 



Both the above species, like the two preceding them, are 

 terrestrial. 



LYGIA OCCIDENTALS. Dana. 



Lygia occidentalis, Dana ; U. S. Exploring Expedition, Crust, ii. 742. 

 PL XLIX. f. 7.— Proc. Acad. Nat. Sci. Philad. vii. 176. 



The Lygiss are isopoda of rather large size, and nearly 

 amphibious habits, generally found running about with 



