82 PROCEEDINGS OP THE ACADEMY OP 



TROCHITA? ANTIQTJA, Meek. 



Shell strongly depressed, subtrocliiforra, about three times as 

 wide as high ; under side flattened and provided with a broad, 

 shallow, excentric umbilical impression; volutions two and a half 

 to three, a little convex, with a gentle outward slope above, and 

 an angular periphery at the connection of the upper slope of the 

 whorls and the base ; suture rather obscure ; aperture transversely 

 rhombic ; nearly three times as wide as high, with acutely angular 

 outer and inner extremities ; upper edge of lip very oblique, and 

 extended far forward beyond that below, which seems to be nearly 

 straight. Surface of upper side ornamented by rather distinct 

 lines, or small ridges of growth, which cross the volutions very 

 obliquely, with strong backward curves as they approach the 

 periphery parallel to the margin of the lip. 



Breadth, 2.12 inches ; height, 0.66 inch. 



The specimens of this shell yet found are very imperfect, but 

 its form and general appearance are so peculiar that there can 

 scarcely be any difficulty in identifying it. Although it has a 

 broad umbilical impression, this impression does not appear to 

 extend up into the very short spire as a true umbilicus. It may 

 not be a true Trochifa, but the specimens yet seen show no cha- 

 racters by which it can be separated from that group, which seems 

 to be represented in the Carboniferous rocks. 



Locality and position. Monclova, Lucas County, Ohio. Cor- 

 niferous group of the Devonian. 



TROCHONEMA TRICARINATA, Meek. 

 Shell turbinate, thin, a little wider than high ; spire depressed. 

 Yolutions about five, strongly shouldered, or nearly rectangular 

 above ; the upper surface being flat, or a little concave, and ex- 

 tended out almost horizontally to the rectangular and carinate 

 shoulder ; below this the outer side is nearly vertically flattened 

 to a second carina passing around near the middle of the body 

 whorl, exactly coincident with the suture between that and the 

 succeeding turn, so as not to be exposed on the spire ; below 

 this second carina the under side of the body volution is flattened, 

 with a strong inward slope, to a third well-defined carina, passing 

 around the middle of the under side, and forming the margin of 

 the umbilicus. Aperture oval-subpentagoual, being a little higher 



[June 6, 



