GASTROPODA. 1011 
Plethospira striata.] 
PLETHOSPIRA STRIATA, 2. sp. (Ulrich.) 
PLATE LXX, FIG. 7. 
Shell turbinate, apical angle at least 85°, hight nearly 22 mm., width about 19 mm.: volutions at 
least four, probably five, convex below, nearly vertical in the middle third, concave above the band, hori- 
zontal between the upper carina and the suture; band supra-median on the last, infra-median on the 
whorls of the spire, decidedly concave, with thick and prominent margins; lines of growth rather regu- 
lar, strong and heavy, rounded, wave-like, five or six on the last whorl in 4 mm.; on the upper side they 
curve strongly backward, beneath the band they are almost vertical saving a very short retral curve 
above; lunule obscure; aperture rounded-pentagonal, outer lip with a broad but very shallow notch, 
columellar lip straight, obtusely angular below, reflexed, completely covering the minute umbilicus. 
This well-marked species cannot be confounded with any other shell known to us. The surface 
markings are highly characteristic. 
Formation and locality.—Richmond group, Hanover, Butler county, Ohio. 
Collection.—H. O. Ulrich. 
Genus SEELYA, n. gen. (Ulrich.)* 
Pleurotomaria, in part, of MEEK and WORTHEN, and WHITFIELD. 
For generic diagnosis see page 958. For figures of typical species see page 1009. 
The species which we propose to arrange under this generic title agree closely 
with Plethospira in all respects excepting that they have a narrower band and a 
spirally furrowed surface sculpture. As the group is easily recognized, a natural 
one, and ranges from the Calciferous to the top of the Niagara, we think that it 
should be distinguished by a name of its own. Whether the group is to be viewed 
as a genus or as a subgenus is of little consequence now. Our knowledge of Paleozoic 
Gastropoda is yet far from that point when we may decide such questions with 
anything like confidence in the stability of the result. 
In the Calciferous of the Champlain valley we have two species of this genus, 
the type, S. ventricosa Ulrich, and Pleurotomaria difficilis Whitfield. These possibly 
are not distinct, but if Whitfield’s figures of his species are correct, and we have no 
reason to doubt it, then it is clearly another form, having a lower spire, more 
numerous revolving furrows, and a shoulder-like angulation near the suture that is 
wanting in 9. ventricosa. An imperfect specimen in the U. 8. National Museum, 
which seems to belong to Whitfield’s species, differs further in having a larger 
umbilical perforation. 
Judging solely by the illustration given by Billings in Paleozoic Fossils, vol. i, 
p. 187, fig. 171, of his Murchisonia cassandra, we would say that the species was 
* The genus is named in honor of Prof. H. M. Seely, of Middlebury College, who, because of his valuable work on the 
Oaiciferous-Chazy fauna and rocks of the Champlain valley, in connection with Prof. Brainerd, has fully earned the com- 
pliment. One of the authors is also indebted personally to Prof. Seely for numerous specimens, among them the type of 
the present genus, from Fort Cassin and other localities in the Champlain valley. These have been of much assistance in 
our work. Some paleontologists probably will contend that the name should have been written Scelyia, but the shorter 
form Seelya seemed so preferable that we concluded to risk their criticism. 
