GASTEROPODA. 49 
Since, however, we have only gutta-percha casts of the exterior moulds, there 
is no satisfactory means of separation. 
Formation and locality. In semicalcareous bands in the Upper Chemung, at 
Nichols, Tioga county, N. Y. 
Loxonema laxa, n. sp. 
PLATE XVIII, FIG. 12. 
Loxonema terebra ? Hall. Illustrations of Devonian Fossils: Gasteropoda, pi. 18. 1876. 
Shell thick, elongated, terebriform; spire very rapidly ascending. Volutions 
rounded, gradually expanded to the last one which is ventricose; col- 
umellar lip greatly extended, making the lower part of the aperture very 
acute; about four and a half volutions in the length of two inches and 
three-fourths from the base—the entire shell having had about one or 
two more. 
Surface marked by coarse, obtuse, elevated striae, which are obsolete on the 
upper part of the volution, and make a very gentle curve over the 
periphery. 
The specimens examined are essentially casts of the interior, sometimes 
preserving portions of the shell which is crystalline and adhering to the 
matrix. Slight indications of the surface markings are sometimes preserved 
on the cast; and in one individual may be seen the strong elevated striae 
characteristic of the genus. The-species has been abundant in the locality 
where it occurs, since, in a single specimen of the rock therefrom, of the size 
of two by three inches, and scarcely more than an inch thick, fragments of as 
many as eight or nine individuals are to be seen. It is associated with numer¬ 
ous specimens of Belleeophon, Pleurotomaeia and Platyostoma ; and the Mac- 
rocheilus ( Holopea) macrostomus, known elsewhere only in the Hamilton group, 
occurs in the same position. 
Formation and locality. In the higher beds of the Chemung group, at Nichols, 
Tioga county, N. Y. 
7 
