90 EOCENE MOLLUSCA. 
In the general contour, and in the proportions of the aperture, the present species 
closely resembles Z. convera; but the small, flat, sulcated fold separates it from that 
species. 
Size.—Axis, 1 inch and 3-10ths; diameter, rather more than 6-10ths of an inch. 
Localities —Headon Hill. French: Pierrelaie. 
Sect. 46. Columellar fold rounded or sub-acute. 
No. 38. Limnza FustFoRMIs. J. Sowerby. Tab. XIII, fig. 8 a—g. 
Lymnm@a FustFoRMIS, J. Sow. 1818. Min. Con., vol. ii, p. 155, tab. 169, figs. 2-3. 
LIMNEA — G. Sow. Genera of Shells. 
= = Lyell and Murch. 1829. Sur les dépéts lacustres, &c., du Cantal. 
L. testd ovato-acutd, sub-fusiformi, levi; anfractibus septenis vel octonis, sub-planis, 
ultimo ventricoso: aperturd ovatd, spiram in longitudinem vix equanti ; columella marginata ; 
plica columellari. rotundatd aut sub-acutd, parum tortuosd. 
Var. DEFORMIS, (fig. 8 c—e,) testd breviort; anfractibus sex vel septem, ventricosioribus : 
apertura rotundato-ovali, spiram in longitudinem superantt ; plicd columellari rotundatd, 
eminentior?. 
A smooth ovate-acute shell, formed of seven or eight whorls, the upper sides of 
which are nearly straight, giving a regular conical form to the spire, which is elevated 
and pointed; the last whorl is ventricose; the lines of growth conspicuous and sharp. 
The aperture is ovate, moderately large, and nearly as long as the spire; occasionally 
the anterior part is somewhat contracted, imparting a sub-fusiform shape to the shell. 
The columellar fold is thick, and, generally, rounded; but sometimes it presents a 
rather sharp anterior margin; it is slightly and gracefully twisted. 
Of this species, as of Z. caudata, a variety occurs (fig. 8 c—e) in which the shell 
is much shorter, the volutions very ventricose, the aperture roundedly ovate, and the 
fold rounded and prominent. 
The contraction of the anterior part of the aperture, causing the fusiform shape to 
which Mr. Sowerby refers, frequently occurs, but it is not by any means a constant 
character ; in fact, the aperture is more generally somewhat effuse, as represented in 
the figure 8. 
This species approaches Z. pyramidalis more nearly than any other of the fossil 
Limnee; ut the flatness of the sides of the spire, and the rounded fold, are 
characters by which it may easily be distinguished. The variety resembles the short 
variety of Z. caudata ; but the whorls are more ventricose, and the fold is not com- 
pressed and sulcated, as in that species. 
Size.—Axis, 2 inches nearly; diameter, 8-10ths of an inch. 
Localities—Hordwell, Headon Hill, Sconce. French: Aurillac in the Cantal. 
