﻿PHILOXENE. 241 



Affinities. — From Eu. circularis and Eu. Hecale this species differs by the slow 

 rate of increase of its whorls. 



From Eu. serpens it is distinguished by its spire being flat or slightly 

 elevated instead of being sunken, and by the distinct elbow upon the upper part 

 of the whorls. 



In some of the specimens the last whorl suddenly changes its horizontal 

 direction so as to give the shell the form of a truncated cone. Thus it differs 

 from the conical species Eu. Dionysius and Ph. philosophus not only by the slower 

 rate of increase of its whorls, but by the cone of its spire being truncated. 



Euomphalus papyraceus, F. A. Romer, 1 appears to have a papyraceous test 

 and still more slowly increasing whorls, and to lie in one plane. 



Porcellia laevigata, Leveille, 2 appears very similar to the specimen figured on 

 PI. XXIII, fig. 19, but differs in the spire being almost equally concave with the 

 umbilicus, and in the flat and lozenge-shaped section of the whorls — points which, 

 in all probability, may be taken to be sufficient to prove that that Carboniferous 

 shell is distinct. 



3. Philoxene serpens, Phillips sp. PI. XXIV, figs. 1 — 5. 



184-1. Euomphalus serpens, Phillips (pars). Pal. Foss., p. 94, pi. xxxvi, fig. 172 



(a and b only). 

 1844. — — Gold/. Petrel'. Germ., vol. iii, p. 88, pi. cxci, 



figs. 8 a, b (Carboniferous). 

 1850. — planorbis, F. A. Romer. Beitr., pt. 1, p. 37, pi. v, figs. 24 a, b. 



1854. serpens, Morris. Cat. Brit. Foss., p. 248. 



1860. — orbis, Eichwald. Lethaea Eossica, p. 1155, pi. xlii, figs. 8 a, b. 



1861. — cltmenoides, Hall. Desc. N. Sp. Foss., p. 26. 



1862. — — — Fifteenth Kep. N. T. State Cab. Nat. 



Hist., pp. 54 and 166, pi. vi, figs. 1, 2. 

 1876. — — — Pal. N. T., vol. v, pt. 2, p. 62, pi. xvi, 



fig. 15 ; and pi. lxx, figs. 1 — 5. 

 1888. — serpens, Eth. Foss. Brit., vol. i, Pal., p. 163. 



Description. — Shell rather small, discoid, very flat, of about five rather slowly 

 increasing volutions. Spire usually elliptically coiled, flatly concave, slightly less 

 so than the umbilicus. Suture deep and very well defined, facing upwards. 

 Whorls almost circular in section, attached to the whorl within by a very narrow 

 portion, so that the shell is hardly involute. Back slightly oblique. Surface 



1 1850, F. A. Bomer, 'Beitr. Harz.,' pt. 1, p. 49, pi. viii, fig. 7. 



2 1835, Leveille, ' Mem. Soc. Geol. Fr.,' vol. ii, pt. 1, p. 39, pi. ii, figs. 12, 13. 



