CRETACEOUS FOSSILS. 191 



MEEKIA, N. Gen. 



Shell equivalve, inequilateral, gaping at both extremities; 

 anterior end produced, and terminating in a hook-like angle 

 above. Surface plain, or marked only by lines of growth. 

 Hinge composed of two robust, triangular teeth on the right 

 valve, and one large and one small one on the opposite side, the 

 large one being received between the two of the right valve ; 

 posteriorly, on each side, is an indistinct lateral tooth. Ligament 

 subexternal ; lunule moderate, lanceolate. Muscular scars two : 

 pallial line simple, or not more emarginate posteriorly than in 

 Trigonia or Tancredia. 



A short, robust plate separates the anterior muscular scar from 

 the cavity of the beak. 



The family relations of this shell arc by no means obvious. 

 The hinge is not unlike that of Lycett's genus, Tancredia, and 

 the pallial line is also of the same form. A marked difference 

 exists, however, in the gaping anterior end, and the angle at the 

 junction of the cardinal and anterior margins. It is probable 

 that these two genera will form the types of a new family. 



It is with pleasure that I dedicate this curious genus fo my 

 friend, Mr. F. B. Meek, of Washington, D. C. 



M. SELLA, n. s. 

 PI. 25, Fig. 179. 



Shell robust, subquadrate ; beaks subcentral, small, nearly 

 touching, and inclined forwards ; cardinal margin strongly 

 arched, descending rapidly, and uniting by a regular curve with 

 the posterior margin, which is sometimes faintly truncated ; 

 anterior end produced, laterally compressed, rounded and re- 

 treating below, and terminating above in a sharp angle, between 

 which and the beak the margin is broadly concave ; base regu- 

 larly rounded, usually most prominent a little behind the beaks. 

 Lunule small, bordered by a single impressed line. The pos- 



