266 
Relations and Differences. — This species is closely related to my L. 
elongaia, to which I at first assigned it. But on close ohservatiou one sees 
that the spiral whorls are much less convex, and that they do not possess the 
upper inflation which characterises those of the species just named; among 
this last also the spiral angle is smaller, being only about 24°, while that of 
difficiUs is 31°. 
Horizon and Localities. — This was found in a grey limestone on the 
hanks of the Kama. 
Loxonema consthicta, W. Martin. 
PI. XXIII, Pig. 20. 
Conchytiotithus Turhinites ? constrietus, W. Martiu, 1809, Petrif. Derbiensis, p. 18, 
pi. 38, fig. 3. 
Melania constricta, J. Sowerby, 1821, Min. Coucb., Ill, p. 33, pi. 218, fig. 2. 
Terehra ? „ 
Melania ,, 
Loxonema 
Chemniizia 
Loxonema 
J. de Carle Sowerby, 1834, Indices Min. Concb., p. 247. 
J. Phillips, 1836, Geol. Yorkshire, II, p. 228, pi. 16, fig. 1. 
L. G. de Kouinck, 1813, Precis Elementaire de Geol., par d’Omalius 
d’llalloy, p. 516. 
Idem, 1843, Descr. Anim. Poss. Terr. Carb. Belg., p. 465, pi. 41, fig. 5. 
P. McCoy, 1844, Synop. Carb. Poss. Ireland, p. 30. 
A. d’Orbigny, 1850, Prod. Pal., I, p. 117. 
J. Morris, 1854, Cat. Brit. Poss., p. 255. 
L. G. de Kouinck, 1873, Eecb. Anim. Poss., II, pi. 4, fig. 5. 
This shell is conical, elongated, of moderate size, and consists of ten 
or twelve spiral whorls, the profile of which is slightly sinuous, owing to a 
gentle swelling towards their upper margin ; their lower margin is ornamented 
with a series of small inflations, or elongated tubercles, produced by the 
successive growths of the shell, and generally corresponding to very fine 
striee produced by the same cause. The aperture is nearly cireular, and 
shows a slight callosity by the side of the columella. 
Dimensions. — This shell can reach a length of four or five centimetres, 
and its last spiral whorl may have a diameter of from fifteen to twenty milli- 
metres, hut the largest Australian specimen sent me is only eleven millimetres 
long, with a diameter of four millimetres. Its spiral angle is about 29°. 
