114 PROCEEDINGS OF THE ACADEMY OF 



along the concentric bands are smaller and more regular. Its nearest foreign 

 analogue is P. punctata, Sowerby, (Min. Conch, iv. 22, pi. 323.) Its surface 

 features, in point of regularity, are intermediate between the extremes pre- 

 sented by that variable species ; but it differs constantly in the absence of a 

 sinus. 



Producta curtirostka, n. sp. Shell of moderate size, semi-globoid, with- 

 out mesial sinus. Hinge line nearly equal to greatest width of valve, with 

 but slight flattening in the region of the extremities. Beak scarcely surpass- 

 ing the hinge line, extremely flattened ; general surface regularly convex, 

 marked by numerous interrupted, sub-obsolete costse, and, in the umbonal 

 region, by numerous concentric wrinkles, most distinct upon the ears. The 

 inside of the dorsal valve presents an appearance very similar to the outside 

 of the ventral valve. 



This is the species formerly referred by me (Proc. Acad. Nat. Sci. Phil., 

 Jan. 1863, p. 4,) to P. speciosa, Hall. A careful comparison of specimens, how- 

 ever, fail to justify this identification. It most nearly approaches P. lacry- 

 rnosa, Hall. The remarkable features of the beak of the ventral valve, and 

 the great concavity of the dorsal, are, however, characters which distinguish 

 this species from all others. P. lacrymosa has less fulness in the region of 

 the cardinal extremities, giving the umbo less breadth and greater isolation 

 from the ears. 



From the yellow sandstone, Burlington, Iowa. " White Collection" of the 

 University of Michigan. 



Producta dolorosa, n. sp. Shell of medium size, somewhat hemispherical, 

 outline subcircular or somewhat transverse, truncated along the hinge line, 

 which is considerably shorter than the greatest width of the shell. Ventral 

 valve regularly convex, with scarcely an apparent flattening at the hinge ex- 

 tremities ; beak depressed, obtuse, slightly surpassing the cardinal line. 

 Dorsal valve but slightly concave, with a low and inconspicuous median sep- 

 tum reaching to the middle of the valve ; the muscular scars presenting 

 together a somewhat semicircular contour, in front of which the interior of 

 the shell presents a finely papillose area. External surface presenting a 

 series of elongated pustules, or interrupted, irregular depressed costse, and a 

 few coarse concentric wrinkles, between which the surface is covered with 

 fine concentric stria?. 



Length from hinge, in a straight line to front margin, -54 (66) ; transverse 

 diameter, -82 (100); length of hinge line, *56 (68) ; depth of ventral valve, 

 24 (29). 



This species, on casual observation, would be referred to P. lacrymosa, 

 Hall, (x. Report New York Regents, p. 177.) The beak, however, is less 

 acute and projecting, the ears less flattened, the dorsal valve less concave, 

 and tlie ventral less produced. If possessed of cardinal spines it might be 

 taken for Chonetes truncata, Hall. Figures D and Dd, Whittlesey, (Proc. 

 Amer. Assoc. Cincinnati, p. 220,) may be intended for this species. 



"Weymouth, Medina County, Ohio, 60 feet below the conglomerate." 

 Whittlesey's Collection. 



Producta concentrica, Hall. In quoting this species from Michigan, 

 (Proc. Acad. Nat. Sci. Phil., Sept. 1862, p. 411,) it was stated that only the 

 interior of dorsal valves had been seen in the southern part of the State. 

 Since then I have obtained good ventral valves from Battle Creek, which agree 

 in every respect with specimens from Burlington, Iowa. 



A dorsal valve of this species was found at Rockford, Indiana, in the bluish 

 argillaceous brecciated limestone of the famous " Goniatite bed." This spe- 

 cies is now known to occur in Northern and Southern Michigan, at Burlington 

 and Rockford, and probablv in Missouri and Illinois. 



[July, 



