So BULLETIN OF THE LABORATORIES 



quite acute, ratlier prominent, curved anteriorly, about two-fifths the 

 entire length from the front, hinge-line gently curved posteriorly, with 

 about ten teeth; anterior margin a gende curve with the focus in the 

 lower margin in front of the middle; lower margin nearly straight be- 

 hind, curving more rapidly as it approaches the front; posterior part 

 of the shell narrow ; the greatest elongation anteriorly is near the 

 juncture of tne lower and anterior margins. Judging from the cast 

 the shell was very thick, no markings being preserved. Length 25 ; 

 height 12; width v^ (?); beak to front 9 ; height of beak above long- 

 est axis 6 mm. 



This is apparently the species identified by Prof. Hall [Pal. N, Y. 

 Vol. V,] with N. pandoriformis, Stevens. The original description of 

 Dr. Stevens seems, however, to forbid the reference. 



Jfitcidana (Leda) saccata, Win. ? 

 (Plate IX, Fig. 12.) 



A single poor specimen from the same horizon as the above bears 

 at least a superficial resemblance to the species quoted. 



Palaeoneilo ellipticus, ^p- i^- 



{^= Palxoneilo concentrica, authors, not cardinia conccntrica, Win- 

 chell.) 



Shell moderately thick, probably gaping somewhat behind, strong- 

 ly and evenly convex ; outline nearly perfectly elliptical ; hinge line 

 extending in front of the beaks, convexly curved posteriorly and con- 

 cave in front ; about twelve oblique teeth in front and about twenty 

 behind ; beaks about one-third to three-fourths the length from the 

 front margin, incurved to near the mediam plane ;. umbo moderately 

 prominent, post-umbonal slope convex, parallel to the hinge-line ; pre- 

 umbonal slope very steej), the umbonal ridge being concave upwards ; 

 lower margin a uniform shallow curve; anterior and posterior outlines 

 strongly and similarly curved. Surface of valves marked by few, dis- 

 tant, very prominent concentric ribs, the intervals being flat or con- 



