48 Crustacea and Echinodermata of the 



DECAPODA MACROURA. 



Tribe THALASSINIDEA. 



gebia pugettensis. Dana. 



Plate XXI. f. 2. 



Gebia Pugettensis, Dana ; U. S. Exploring Expedition, Crust, i. 510, PI. XXXII. 



f. 1. 

 Gebia Californica, Stimpson ; Proc. Cal. Acad. Nat. Sci. i. 88. 



The Gebia may be distinguished from the other fossorial 

 Macroura of this coast, by its rough, hairy rostrum, and 

 equal anterior feet. 



The thumb in this species (see the figure) is considerably 

 curved, and bears on its inner side a strong tooth. This 

 tooth is a prominent character in all the very numerous 

 specimens in the Smithsonian Museum, but is obsolete in 

 the specimen described by Dana, although actual compari- 

 son shows them to be the same. The species attains a 

 large size, the dimensions of an Oregon specimen being as 

 follows : — 



Length of the animal 4.00 inches 



'• " carapax 1.38 " 



" " hand 1.00 " 



Width " carapax .80 " 



" abdomen . . . . . . 1.05 " 



" hand 46 " 



A curious parasitic bivalve, apparently new, both in 

 genus and species, is frequently found adhering by its 

 byssus to the inner surface of the abdomen of this crus- 

 tacean. It approximates in character to the genus Lepton. 



Gebia Pugettensis is found on the whole coast from 

 Puget Sound to Monterey. It excavates its subterranean 

 chambers in the sand and mud of beaches, near low-water 

 mark, preferring that which is more or less indurated. 



