620 SYSTEMATIC PALEONTOLOGY 



slightly convex, the ventral broadly and feebly constricted ; external sur- 

 face smooth excepting for a rather vigorous incremental sculpture; liga- 

 ment submarginal, opisthodetic ; hinge edentulous; adductor scars and 

 pallial characters obscure. 



Dimensions. Altitude 5 mm., latitude 13 mm., semi-diameter 

 3.5 mm. 



The remains of this small borer are found in the tests of Exogyra and 

 Pycnodonte. It differs from L. ripleyana, which it most strongly 

 resembles, not only in its habitat but also in the less inflated valves and 

 less produced posterior extremity. 



Occurrence. MONMOUTH FORMATION. Brightseat, Prince George's 

 County. 



Collection. Maryland Geological Survey. 



LITHOPIIAGA JULIJE (Lea) 

 Plate XXXVI, Figs. 10, 11 



Modiola Julia; Lea, 1862, Proc. Acad. Nat. Sci., Phila. for 1861, p. 149. 

 Modiolus Julice Meek, 1864, Check List. Inv. Fossils N. A., Cret. and Jur., 



p. 11. 



Perna Julite Conrad, 1868, Cook's Geol. of New Jersey, p. 726. 

 Modiola Julia Whitfield, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 64, pi. xvii, 



fig. 6 (not fig. 7). 



Modiolus Julia Johnson, 1905, Proc. Acad. Nat. Sci., Phila., p. 12. 

 Modiolus Julicc Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, p. 506 



(ex parte, description and figures excluded). 



Description. " Testa transverse striata, subrhomboidea, subinflata, 

 postice oblique truncata, inferne emarginata; valvulis fragillissimis; nati- 

 bus prominulis, fere terminalibus. Length .23, breadth .36 of an inch." 

 Lea, 1862. 



Type Locality. Haddonfield, New Jersey. 



Shell nacreous, excedingly thin and friable ; transversely ovate in out- 

 line, compressed ; umbones placed within the anterior seventh of the shell, 

 not prominent but evenly rounded, proximate, incurved and slightly 

 prosogyrate ; anterior end of shell feebly expanding in front of the beaks ; 

 posterior dorsal margin approximately horizontal; posterior lateral mar- 



