34 NEW YOEK STATE MUSEUM 



small size and quite considerable convexity. The beak is subcentral, the 

 outline and contour slightly oblique and the wings not distinctly 

 separated from the body of the valve. The surface bears from 40 to 

 50 fine radii, the majority of which arise by dichotomy over the 

 median parts of the valve, but all have about the same size and are 

 equidistant on the margin. These are crossed by extremely fine, con- 

 centric lines and a few obscure undulations. 



The convexity of this valve shows the relation of the species to 

 those later Devonic shells which have been referred by Hall to the 

 subgenus Vertumnia. 



Aviculopecten sp.? 



A small right valve of orbicular outline has deeply concave wings 

 and a depressed surface with extremely faint and fine radii. 



Lyriopecten sp. ? 



An imperfectly retained right valve has very obscurely defined 

 wings, the anterior wing not interrupting in any way the convexity of 

 the shell. The surface is cancellated by fine radii in several series, 

 crossed by concentric, erect lines. 



Actinopteria communis Hall 



Plate 4, flg. 1, 2 



1859. Avieula communis Hall, Paleontology of New York. 3 : 286, pi. 51, 

 fig. 1-7; 53, fig. 4, 6 



To this species is referred a shell which attains the size of average 

 specimens of Actinopt. communis and is ornamented by radii of 

 alternate or unequal size, crossed by low, concentric erect lamellae. On 

 the an tenor surface of the left valve these striae produce a sharp can- 

 cellation and on the large and flat posterior wing radial and concentric 

 lines are of about the same size. On the right valve the wing is can- 

 cellated but on the body of the shell the concentric lines are absent, 

 and the radii are distant and not alternate. This rare shell in the 

 < )riskany seems to agree with the characters of Actinopt. com- 

 m u n i s of the Helderbergian, though it also approaches the Actin- 

 opt. textilis Hall of the same fauna. 



