380 PALEONTOLOGY OF NEW-YORK. 



Genus Gypidula (n.g.). 



[Qr.}vi>, vultur ; in allusion to the strongly incurred beak.] 



Geneeic characters as given on page 373 of this volume. 



Type G. accident alls. 



Gypidula occidentalis. 



PLATE LVIII. 



Pentaments occidentalis : IIall, Geology of Iowa, Vol. i, part ii, pa. 514, pi. ri, f. 2. 1858. 

 Not <• " Idem, Pal.New-Tork, Vol. II, p.3Jil. 1852. 



Shell subovoid, gibbous, very inequivalve ; hinge-line equalling three- 

 fourths the entire width of the shell. 



Ventkal valve arcuate, gibbous or ventricose in the upper part ; beak 

 extended, strongly incurved, obtuse ; fissure large and bordered by a 

 distinct area which is vertically striated. The spoon-shaped pit is 

 deep, extremely extended and incurved. The middle of the valve, 

 below the first third, elevated into a more or less distinct mesial fold 

 which is marked by two or three plications. 



Dorsal valve gibbous above, becoming flattened below the middle, some- 

 times concave at the sides, and the front depressed into a deep and 

 more or less distinctly defined sinus. A narrow area extends for about 

 two-thirds the length of the hinge-line. 



Surface plicated below by a few rounded or subangular plications which 



become obsolete above ; the upper part of the valve marked only by 



concentric striae. , 



Geological formation and locality/. In strata of the age of the Hamilton group, 

 at Independence, Iowa. 



