Notes on Cincinnatian Fossil Types 
317 
Economy member of the Eden group, at Cincinnati, Ohio. The 
length of the type is 5 mm., the width is only slightly less, and the 
height is about 1.7 mm. The apex is about two-fifths of the length 
of the shell from the posterior margin, so that the concentric striae 
are crowded posterior to the apex. The concentric striae are thick, 
strong, and salient for a shell of such small size. The prominence 
of the striae becomes gradually less from the margin toward the apex. 
The exterior three are strong, the next three vary from medium to 
fine, and the last three, toward the apex, are almost obsolete in the 
type, but this may be due in part to wear. 
A second specimen, in the Dyer collection, is slightly larger, 
and is marked by 12 concentric striae. The outer striae in this speci- 
men are not so strikingly larger and coarser than those nearer the 
apex as in the type specimen. 
27. Crania percarinata, Ulrich 
{Plate VI, Fig. 1; Plate IV, Fig. 7) 
1878. Crania percarinata Ulrich, Jour. Cincinnati Soc. Nat. Hist., 1, p. 98, Plate 
I, Fig. 12 
1892. Crania percarinata {—Crania scabiosa Hall) Hall and Clarke, Pal. New 
York, 8, pt. 1, Plate IH, Fig. 30 
The types of Crania percarinata belong to the collection of 
Prof. Charles Schuchert, of Yale University, and were found in the 
Economy member of the Eden, about 100 feet above low water in 
the Ohio river, at Covington, Kentucky. 
The specimen illustrated by figure 30, in the Hall and Clarke 
publication cited above (fig. 1 on plate VI and fig. 7 on plate IV 
of present bulletin), is 3 mm. in length, 4.1 mm. in width, and has a 
convexity slightly exceeding one millimeter. In life it was attached 
to a specimen of Lophospira lirata Ulrich, which probably is identical 
with the species described by James as Murchisonia ohioensis. The 
upper valve of this Crania carinata, the only valve known, reproduces 
in a remarkable manner even the minute striations of that part of 
the Lophospira upon which it grew. The specimen rested directly 
upon the trilineate slit-band and extends from this band upward 
sufficiently to include the carina on the upper slope of the whorl, 
and downward beyond an apparently nearly obsolete carina on the 
lower slope. The markings on the Crania indicate that the slit- 
band had a width of 0.7 mm., transverse striae approach this slit- 
band both from the upper and lower slopes of the whorl so as to curve 
