13 



LIOPTERIA S0IJOVATA, 11. sp. 



Plate II, Fiij. 7. Ji'fl ralre; [xirl of the car broken awaij : Fiij. 8, 



right LHilve of iinotlier specimen: Fig. 'J, left valve 



of (uioilier specimen. 



Species medium size, subrhomboidal. Body obliquely sul)Ovate. 

 Auterior margin nearly straight above aud abruptly rounded into 

 tbe basal margiu below. Basal maryiu narrowly rounded. Pos- 

 terior margin somewliat straight above and abruptly rounded into 

 the basal margin below. Hinge line straight from the auterior 

 side of the beak to the posterior extremity, aud nearly as long as 

 the shell. Beak of each valve obtuse and situated near the an- 

 terior side of the shell. It is separated from a short ear l>y an 

 undellLed longitudinal sulcus. Both valves are moderately gii)- 

 bous, the left valve rather more conve.x than the right. The pos- 

 terior umboual 8loj)e is rounded and soon merges into the geueral 

 convexity of the shell. The wing is Hat and terminates in a long 

 acute extremity. The shell is marked with concentric lines of 

 growth. 



All of our specimens are casts and the left anterior ear is 

 always injured. No radiatiug lines are discernable. 



This is a shorter form with a larger wing than L. speciosa, 

 and its general outline will distinguish it from all othfer species. 



Found by R. A. Blair, in the Chouteau limestone, near Sedalia, 

 Missouri, and now iu the collectiou of S. A. Miller. 



LIOl'TEllIA aPECIOSA, U. Sp. 



Plate II, Fig. lo, left ralrc, sligliihj hro1;en anterior to the heal'. 



Species rathi'r above medium size, subrhomboidal. Body narrow 

 above aud oi)li(juely elongate ovate. Aiiterit)r margin lnou'lly 

 roundeil above aud abruptly curving into the banal iiiiigiii I clow. 

 Posterior luargin nei rly straight until it rounds iiil') the bashl 

 margin. Hinge line straight from the au'erior side uf the beid< 

 to the posterior extremity aud about half the length of the slu'll. 

 Bc^ak of the left valve obtuse and situated near the auterior end 

 of the shell. It is separated frjiii a short ear by au undelined 

 longitudinal sulcus. The uuibonal region is somewliat gil^boiiF, 

 but the greater gibbosity of the vilve is in the miildle pait. 

 The posterior wub >u'tl si j[)e is sub:ur<ulHr aljuve l)ut grailuHlly 



