198 NORTH AMERICAN INDEX FOSSILS. 



30. L. melie Hall. (Fig. 232, b.) Lower Carbonic. 

 Generally smaller than preceding, with curving sides and acute 



beak, below which is a narrow flattened space gradually widening 

 to base. Growth lines crowded at intervals; radiating striae 

 obscure. 



Waverly of Ohio. 



31. L. umbonata Cox. (Fig. 229, k.) Upper Carbonic. 

 Of medium size, thin, elliptical with regularly rounding margins 



and prominent umbonal portion. Surface smooth except for lines 

 of growth. 



Coal Measures of Kentucky, Ohio, Iowa, and Missouri. 



32. L. subspatulata Hall and Meek. Upper Cretacic. 

 Of moderate size, oblong. Lateral margins only slightly curved, 



narrowing the shell toward the front. Anterior margin subtrun- 

 cate. Surface marked by fine concentric striae. 

 Nebraska, New Mexico, Manitoba. 



X. Lingulasma E. O. Ulrich. 



Large, thick-shelled Lingulae. Brachial valve much the deeper. 

 Muscles of both valves situated upon a platform which extends 

 over one- half the length of the shell ; that of the pedicle valve is 

 low ; that of the brachial is high and is continued anteriorly as a 

 strong septum. No pedicle opening present. Deltidium present 

 and probably entirely internal, thus forming a sheath resting upon 

 the posterior portion of the pedicle platform. Ordovicic. 



Fig. 233. Lingulasma galenaense ; interior view of ventral and dorsal valves, and 

 profile of inner mold with outline of shell dotted in (cr, crescent ; g, umbonal scar ; h t 

 central scars ; /, anterior scars ; k, middle scars ; /, lateral scars ; s, septum ; /, 

 transverse scars. X '• (After Winchell & Schuchert, Min. Pal.) 



