OF DENISON UNIVERSITY. 59 



anterior projection is apparently acute, the lower margin formincr an 

 angle of 3o°-4o° with the hinge. The posterior wing is imperfect, 

 but was probably slightly produced. Fig. 20 of Plate IV, is certainly 

 wrongly restored, being, without doubt, the same species as the one 

 first referred to. The relation to certain Chemung species, especially 

 Pt. inoptatus, is very close. 



Lepfoflesma (?) scutella, sp. n. 



(Plate IV, Fig. 16.) 



A number of specimens of a little shell at first referred to Pteron- 

 ites indicate a species belonging to section umbonata, but apparently 

 distinct from any Chemung species. Sub-rhomboidal or nearly semi- 

 ovate, anterior wing short, acute; body inclined about 50° to the 

 hinge line, which it about equals ; posterior margin concave, upper 

 angle produced, beak sub-anterior; surface gently convex, except the 

 y^osterior wing, marked by equidistant lines of growth. With the 

 above. 



Posidonomija 'Strehloptrriai firtgUis, '■P "■ 

 (Plate VI, Fig. i.) 



The specimens on which this species is founded differ from all 

 Waverly species and all others known to me. The species may be 

 compared with P. laterugata, but is less alate and has much more prom- 

 inent beaks. 



The wings are almost too prominent for a member of the genus 

 quoted and the presence of indistinct radiating strice passing over the 

 coarse plications adds to the incongruity. 



The right valve is broadly oval or nearly circular, with the poste- 

 rior ear considerably produced, anterior one less distinct and shorter, 

 margin below the ears a reniform broad curve resembling a circle ; 

 surface of the valve rather flat, but somewhat suddenly elevated near 

 the beak, which is acute and slightly projecting beyond the hinge ; 

 hinge line straight, rather short ; surface marked by distant irregular 

 folds and indistinct, fine, minute radiating strue. Height 29 mm ; 



