208 



NEW YORK STATE MUSEUM 



V. 



Genus liopteria Hall 



[Ety.: Ash)?, smooth; -zepov, win^] 



(1883. Pal N. Y. V. 5, pt I, p. 4) 



Shell aviculoid, oblique, subrhomboidal ; anterior end not auricu- 

 late; wing large, extremity produced. Hinge narrow, furnished 



with a slender lateral tooth just pos- 

 terior to the beak and nearly parallel 

 to the hinge line. Ligament external; 

 ligamental area narrow, extending 

 the entire length of the hinge, marked 

 by fine, sharp, longitudinal striae. Test 

 with concentric striae but without rays. 



Liopteria ( ?) subplana (Hall) (Fig. 

 136). Avicula subplana Hall 

 (1852. Pal N. Y. 2:2Ss, pi. 59) 



Distinguishing characters. Depressed 

 convex surface; similarity of right and 

 left valves; ill defined wing and ear; 

 concentric striae; absence of radii. 

 Found in the Rochester shale at 

 Lockport associated with Pterinea emacerata, etc. (Hall). 

 Probably also at Niagara. The generic reference is provisional. 



Genus lyriopecten Hall 



[Ety.: Au/>£ov, small lyre; pecten, comb, i. e. the genus Pec- 

 ten] 



(1884. Pal N. Y. V. 5, pt I, p. 12) 



Shell inequivalve, with a short hinge line and very small anterior 

 ear. Cartilage in shallow furrows^ parallel to the hinge margin. 

 Surface ornamented with rays. 



Lyriopecten orbiculoides (nom. nov.) cf. Avicula (?) or- 

 b i c u 1 a t a HaU (1852. Pal N. Y. 2:284, pi. 59) 



Distinguishing characters. Right (?) valve convex; left (?) valve 

 flat; form suborbicular, hinge line short, straight; strong radiating 

 striae cancelated by equally strong concentric striae, forming sur- 

 face similar to Pterinea emacerata. 



Fig, 136 Liopteria (?) subplana 



