NATURAL SCIENCES OF PHILADELPHIA. 
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acuminately tapering toward the opposite extremity. Anterior side nearly 
straight, or distinctly hollowed. Posterior side parallel with the anterior for 
half its length ; toward the hinge gradually approaching the opposite side. 
The truncation is at right angles with the anterior side, leaving a broadly 
gaping ventral margin. External surface smooth. 
Length dorso-ventrally *97 (100) ; greatest dimension at right angles with 
this *26 (27) ; thickness of both valves *12 (12). 
Collected by A. Winchell at Napoleon cut, Jackson County, Michigan 
MYALINA, De Kaninck. 
Myalina Jbowensis, n. sp. Shell rather small, ventricose, obliquely elon¬ 
gate-quadrate. Umbonal ridge elevated, arched, highest about midway be¬ 
tween the beak and the opposite end, forming an angle of 50° with the straight, 
somewhat elongate hinge line ; anterior and posterior sides parallel, the former 
distended in a very shallow pouch just beneath the beak, the latter very 
slightly hollowed throughout its upper half; basal region regularly rounded, 
with an obtuse angulation next the posterior side. From the umbonal ridge 
the slope is precipitous to the anterior margin, much less so toward the pos¬ 
terior, and it gradually subsides into a flattening toward the dorso-lateral 
angle. Surface of shell nearly smooth, marked with fine incremental lines. 
Greatest dimension—from beak to opposite extremity—*83 (100); length of 
'hinge line *46 (55) ; diameter, at right angles with umbonal ridge, '41 (50). 
From the base of the Burlington limestone, “ White Collection, ” of the 
University of Michigan. 
This species resembles M. angulata, Meek and Worthen, from the Chester 
limestone of Illinois, and M. Micliiganensis , Winchell, from the Marshall group 
of Michigan. From the former it differs greatly in its smaller size, its shal¬ 
lower posterior concavity, and its less abruptly rounded base. From the 
latter it differs in having straighter anterior and posterior sides, giving it a 
more quadrate outline, a more elevated umbonal ridge, and a shorter antero¬ 
posterior dimension. 
Myalina Michiganensis, Win. Collected by A. Winchell at Napoleon Cut, 
Jackson County, and at Germain’s Quarry, Hillsdale, Hillsdale County, Mich. 
Edmondia ? bicarinata, Win. A species apparently identical with this 
occurs in a conglomerate four miles north of Panama, Chataque County, New Jf 
York, supposed by Prof. Hall, in his Report on the Fourth District of New 
York, to constitute a portion of the Millstone Grit of Pennsylvania. It was 
figured and briefly characterized under the name of Cypricardia contracta , ^ 
Hall. The later specific name must therefore be abandoned. 
Edmondia .sequimarginalis, Win. Specimens clearly identical with this 
occur in the same conglomerate with the above, as also in a conglomerate at 
another locality, supposed by Prof. Hall to underlie the Millstone Grit, and 
to constitute the terminal member of the Chemung Group. 
The specimens of these two species occurring in New York, as well as the 
two others to be mentioned, are preserved in Prof. Hall’s cabinet; and I desire 
to acknowledge my great obligations for the opportunity afforded of making 
the direct comparisons. 
Edmondia Burlingtonensis ? White and Whitfield. A lamellibranch, too 
imperfect for certain determination, but closely resembling the above, occurs 
in Whittlesey’s Collection, from a place “one mile east of Orange Center, 
Cuyahoga County, Ohio, 25 or 30 feet below the Grindstone Grit.” 
SANGUINOLITES, McCoy. 
Sanguinolites strigatus, n. sp. A small species, resembling Area modesta 
Win., from Burlington, Iowa. Unfortunately the specimen was lost while 
awaiting a description. It had, however, been investigated and its generic 
1865 .] . 
