114 
PROCEEDINGS OP THE ACADEMY OP 
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 curtirostra, 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- 
mosa, 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 costae, and a 
few coarse concentric wrinkles, between which the surface is covered with 
fine concentric striae. 
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 tbe 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 “Groniatite bed.” This spe¬ 
cies is now known to occur in Northern and Southern Michigan, at Burlington 
and Rockford, and probably in Missouri and Illinois. 
[July, 
