AMN. — ANA.] 



LAMELLIBRANCHIA TA. 



461 



Fig. 771.— Ambonychia 

 radiata. 



planistriata, Hal], 1861, Geo. Rep. Wis., 

 p. 32, Trenton Gr. 



radiata, Hall, 1847, 

 Pal. N. Y., vol. 1, 

 p. 292, Trenton, 

 Hud. Riv. Grs., 

 andMid.Sil. Prob- 

 ably a syn. for A. 

 carinata. 

 rauchi, McChesney, 

 1860, New Pal. 

 Foss., p. 89, Hud. 

 Riv. Gr. Not rec- 

 ognized, 

 retrorsa, S. A. Miller, 

 1878, Jour. Cin. 

 Soc. Nat. Hist., vol. 1, p. 104, Hud. 

 Riv. Gr. 

 robusta, 8. A. Miller, 1880, Jour. Cin. Soc. 

 Nat. Hist., vol. 3, p. 315, Hud. Riv. Gr. 

 slrisecosta, see Pterinea striseeosta. 

 superba, Billings, 1866, Catal. Sil. Foss. 



Antic, p. 50, Anticosti Gr. 

 swanana, Safford, 1869, Geo. of Tenn. Not 



defined, 

 undata, Emmons, 1842, (Pterinea undata,) 

 Geo. Rep. N. Y., p. 395, and Pal. N. Y., 

 vol. 1, p. 165, Black Riv. and Trenton 

 Grs. Possibly belonging to an unde- 

 fined genus. 



large triangular cartilage pit beneath 

 the beaks, and smaller pit just anterior. 

 Type A. leidyi. 



Fig. 773.— Amphiccelia costata. 



costata, Hall & Whitfield, 1875, Ohio Pal., 



vol. 2, p. 140, Niagara Gr. 

 leidyi, Hall, 1867, 20th Rep. N. Y. Mus. 



Nat. Hist., p. 387, Niagara Gr. 



Fig. 772.— Amnigeula catskillensis. 



Amnigenia, Hall, 1883, Pal. N. Y., vol. 5. 

 [Ety. amnis, a river; gigno, to bear.] 

 Like Anodonta in form and external 

 . characters; anterior muscular impres- 

 sions large and prominent; posterior 

 ones large and shallow. Type A. cats- 

 killensis. 

 catskillensis, Vanuxem, 1842, (Cypricar- 

 dites catskillensis,) Geo. Rep 3d Dist. 

 N. Y., p. 186, and Pal. N. Y., vol. 5, p. 

 516, Catskill Gr. 



Amphkxelia, Hall, 1868, 20th Rep. N. Y. 

 Mus. Nat. Hist., p. 386. [Ety. amphi, 

 both ; koilos, hollow.] Equivalve, ine- 

 quilateral, subrhomboidal ; umbones 

 gibbous; beaks elevated and incurved; 

 external ligamental area flattened ; 



neglecta, McChesney, 1861, (Ambo- 

 nychia neglecta,) Pal. Foss., p. 88, 

 and Geo. Sur. 111., vol. 3, p. 358, Niag- 

 ara Gr. 



Amphidesma delafieldi, Castelnau, 1843, Syst. 

 Sil., p. 44. Not recognized. 



Anatina, Lamarck, 1809, Phil. Zool.* T [Kty. 

 pertaining to the duck, or like the 

 duck's bill.] Oblong, ventricose, atten- 

 uated, and gaping posteriorly : umbones 

 fissured ; spoon-shaped cardinal process 

 in each valve. Type A. rostrata. Not 

 a Palaeozoic genus. 

 leda, Hall, 1860, 13th Rep. N. Y. Mus. 

 Nat. Hist., p. 110, Ham. Gr. Not prop- 

 erly defined. 

 sinuata, see Ilionia sinuata. 



