994 PROCEEDINGS OF THE NATIONAL MUSEUM. FOI, HRN, 
one to Harttina, with which it agrees in internal structure certainly 
more closely than with any other Terebratuloid genus known to me. 
[Tarttina indianensis seems to be the first occurrence of this genus 
noted in the Mississippi Valley and is of somewhat especial interest 
gn that account. 
Locality and horizon—sSt. Louis group; Pella, Marion County, 
Towa. 
T'ype-specumens. 
Cat. No. 9288, U.S.N.M. 
TEGULIFERA ARMATA, new species. 
Plate XX, figs. 1-11. 
Shell rather small, generally conical but very irregular. Rapidly 
expanding. The blunt cone has no distinct apex, and in fact the 
_ apex is more or less truncated, owing to what appears to be a surface 
of attachment. 7 
The rim, especially toward the front and sides, is armed with large 
stout spines, which sometimes project upward and sometimes inward 
over the aperture. The rim is occasionally double, or even treble, 
consisting of independent concentric plates with spaces between. 
One or all of them apparently may be spiniferous, or the spines 
may project from the inner surface of the aperture. Sometimes, 
though very rarely, the development of the spines is attended by the 
appearance of coste, which are rather few and faint and restricted 
to the vicinity of the rim. | 
The rest of the surface is marked by fine, irregular incremental 
lines, by irregular varices of growth, and by a few small spines, 
which are not mounted upon spine bases. There are also frequently 
two or three irregularly disposed, buttress-like ridges, chiefly devel- 
eped near the area of attachment, which are possibly spines adnate 
to the surface. Whether the consecutive lamellae which sometimes 
appear at the aperture are due to the overlapping of different layers 
of shell, as was observed by Schellwein in Vegulifera deformis % or 
to a cessation of growth and a renewal within from a lower level 
than the aperture, a process not infrequently observable in the cup 
corals, has not been determined. 
The dorsal valve is oval in shape, with a very short hinge line, 
nearly flat, slightly concave and of opercular form. It is situated 
well down near the base of the conical ventral valve and is marked 
only by fine incremental lines. 
Apparently the ventral valve in process of growth wraps around 
the dorsal valve and around itself also. The lower portion of the 
ventral valve is, therefore, rather thick and in some cases diminished 
suddenly at the level of the dorsal, forming a sort of shelf or plat- 
form, from which some of the spines are developed. The thickened 
lower portion is sometimes occupied by a few large cysts. 
“k. k. Geol. Reichsanstalt, Abhand., XVI, Heft 1, 1900, p. 59 et seq. 
