94 SYSTEMATIC PAI,EONTOLOGY 



ARTHROPODA. 



Class CRUSTACEA. 



Superorder MALACOSTRACA. 



Order DECAPODA. 

 Family CANCROIDEA. 



Description. — Claws belonging to an indeterminate genus of the 

 Canceoidea are abundant at many localities. They indicate an animal 

 of considerable size and abundance. The remains are largest and most 

 abundant in the Choptank formation. 



Occurrence. — St. Mary's Formation. Cove Point. Choptank 

 Formation. Jones Wharf, Governor Run, 2 miles south of Governor 

 Eun, Dover Bridge, Cordova, Trappe Landing, Peach Blossom Creek, 

 Greensboro. Calvert Formation. Plum Point, Chesapeake Beach. 



Collections. — Maryland Geological Survey, Johns Hopkins University. 



Superorder CIRRIPEDIA. 



Order THORACICA. 



Family BALANIDAE. 



Genus BALANUS Lister. 



Balanus concavus Bronn. 

 Plate XXXIII, Figs. 1-6 ; Plate XXXIY, Figs. 1-7. 



Balanus concavus Bronn, 1831, Italicus Tertiar-Gebilde. 



Balanus finchii Lea, 1833, Contrib. to Geol., p. 311, pi. vi, fig. 233. 



Balanus proteus Conrad, 1834, Jour. Acad. Nat. Sci. Phila., vol. vii, p. 184. 



Balanus proteus Conrad, 1845, Fossils of the Medial Tertiary, No. 4, p. 77, pi. xliv, 



fig. 1. 

 Balanus proteus Conrad, 1843, Proc. Nat. Inst., Bull, ii, pp. 184, 187. 

 Balanus concavus Darwin, 18.54, A Monograph of the Fossil Balanidie and Verru- 



cidiie of Great Britain, p. 17, pi. i, figs. 4a-4p. 

 Balanus concavus Meyer, 1888, Proc. Acad. Nat. Sci. Phila., vol. xl, p. 170. 

 Balanus proteus Whitfield, 1894, Mon. xxiv, U. S. Geol. Survey, p. 141, pi. xxiv, 



figs. 18-33. 



