24 PALEONTOLOGY OF NEW YORK. 



sinus, and from the sides of the umbo by a sulcus ; the hyssal sinus is dee}) and 

 rounded. 



Test marked by fine alternating filiform radiating striae, which are absent 

 on the ears, except as two or three alternating undulations. Fine lines of 

 growth mark the test and extend over the ears. 



Ligamental area linear and marked by an inflection of the hinge-margin. 



The specimen has a height of 15 mm. and a length of 13 mm., hinge- 

 line 111 mm. About 13 rays occupy the space of 5 mm., measured near the 

 basal margin. 



This form may he distinguished by its equilateral proportions, acute, 

 straight apex, the non-oliliquity of the transverse axis to the hinge-line, the 

 broad, triangular ears and the alternating surface stria?. These characters sepa- 

 rate it from A. striatus, to which it is most nearly allied. 



Formation and locality. In sandstone of the conglomerate, associated with 

 the upper Chemung group, at Salamanca, Cattaraugus county, N. Y. 



AviCULOPECTEN PATULUS. 



PLATE VII. FIGS. ::-J. 33. 



Avieulopecten pattd-us, Ham.. Pal. N. V.. vol. v. )>t. I. Plates and Explanations: PI. !'. ti-rs. 32, 33. 



Jan.. 1883. 



Shell large, longitudinally hroadly elliptical ; height about five-sixths as great 

 as the length. The axis of greatest height is at right angles to the hinge, 

 and the line of greatest length is parallel to the hinge and across the middle 

 of the shell. Basal margin convex, somewhat flattened in the middle. 

 Lateral margins very full, and curving rapidly to the ears. 



Valves convex, the convexity equal to one-fourth the length of the hinge- 

 line. The right ami left valves do not differ conspicuously in character, so 

 far as observed. 



Hinge-line apparently straight, equalling nearly two-thirds the length of 

 the shell, central, not extending as far as either lateral margin. 



