GASTROPODA. 927 
Oarinaropsis cunula.] 
Granting for the present that Pterotheca is a pteropod, we look in vain among 
the other types of that sub-class of shells for anything corresponding to the trifid 
apex of Pterotheca. We conclude, therefore, that the peculiarity is of generic 
importance only, and consequently not a serious objection to an arrangement 
which, in following the suggestion of the other characters, would bring Carinaropsis 
and Pterotheca within the limits of the same order and family. According to our 
opinion this family will prove to belong to the Docoglossa and not to the Pteropoda. 
CARINAROPSIS OUNUL& Hall. 
PLATE LXII, FIGS. 10—13. 
Carinaropsis (Phragmostoma) cunulcee HALL, 1861, Fourteenth Rept. N, Y. St. Cab. Nat. Hist., p. 94. 
Shell 20 mm. to 25 mm. in width, the length of the largest specimens about 20 
mm., the hight of the same about 10 mm.; consisting of two. or two and one-half 
volutions, the last abruptly expanded. Dorsum angular, or slightly carinated on 
the small volution, the angle becoming gradually more and more obtuse toward the 
deeply emarginated anterior edge, where it may be quite obsolete and in some 
specimens replaced by a broad flattened slit-band. Umbilicus small but distinct and 
deep. Aperture broadly subovate, insinuated in front and somewhat truncated 
behind; posterior lip reflected. Septum broad, extending about two-fifths across the 
aperture from the edge of the posterior lip, nearly twice as wide as long, its anterior 
edge somewhat thickened and slightly arched; behind the edge, which is nearer the 
plane of the apertural margin than usual, the outer surface is moderately concave. 
Inner surface of septum distinctly carinate, with a slight continuation of the same 
feature on the outer side. Inner aperture subtriangular or semi-elliptical, closed 
by a nearly flat operculum. Surface marked by fine lines and more or less obscure 
varices of growth. 
This species differs from C. cymbula Hall in having the first volutions larger and 
projecting farther beyond the posterior lip, which again is more abruptly deflected, 
but the best difference lies in the septum whose outer surface is much less excavated 
in this species. 
Formation and locality.—Upper part of Trenton group, Nashville, Tennessee, and Boyle county, 
Kentucky. 
Collection.—H. O. Ulrich. 
CARINAROPSIS OymBULA Hall. 
PLATE LXII, FIGS. 1—4. 
Carinaropsis (Phragmostoma) cymbula HALL, 1861, Fourteenth Rept. N. Y. St. Cab. Nat. Hist., p. 94. 
Phragmostoma natator (in error for cymbula) HALL, 1862, Fifteenth Rept. idem., pl. v1, figs. 12—14. 
Volutions one and a half or two, the first very minute; posterior margin of 
