ENANTIOSPHEN. 97 
Localities.—I have about seventeen specimens from Lummaton, and there are 
seven in the Woodwardian Museum and one in the Museum of Practical Geology. 
From Wolborough there are five specimens in Mr. Vicary’s Collection, nine in the 
Museum of Practical Geology, four in the British Museum. From Chircombe 
Bridge are two specimens in the Museum of Practical Geology. 
Remarks.—These specimens are of all sizes. The smallest of mine is much 
smaller than any of those figured by Davidson. It has an open area, and shows 
fine undulating rounded striz or rays on its surface, which are fewer and coarser 
than those seen in larger specimens. Its ventral valve is also marked by several 
ridges of growth. Another specimen, which is very little larger, has the area 
closed and pierced by an oval aperture. The large specimens from Lummaton 
are for the most part bad, with the surface decoriated and so obscured by matrix, 
&c., that their identity is frequently doubtful; but it is clear that it is not an 
uncommon shell at that locality. The size of the beak seems very variable. 
Maurer mentions a species of Barrande’s’ from Bohemia distinguishable by its 
narrow hinge-line. One of the specimens, however, in the Museum of Practical 
Geology, figured by Davidson has its area exceedingly small. 
2. Gienus.—ENANTIOSPHEN,’ Nov. gen. 
This genus can be only provisionally suggested, as its internal arrangements 
are very imperfectly known. A strong median septum in the ventral valve, 
bearing oblique dental processes, distinguishes it, as Mons. Chlert points out, from 
Meganteris, which in many external characters it resembles. The small elevated 
beak with sharp beak-ridges, the minute apical foramen, the flattened geniculated 
valves, and the unpunctured surface are other characteristics, but its true affinities 
remain to be ascertained. 
1. EnantiospHen Viocaryi, Davidson, sp. Pl. XI, figs. 5—8. 
1864. “Species undetermined,” Davidson. Brit. Foss. Brach., vol. iii, pt. 6, pl. xx, 
figs. 15—15 db. 
1882. Meraanteris? Vicaryt, Davidson. Ibid., vol. v, pt. 1, p. 20, pl. iii, figs. 
1—1 8. 
Localities.— Besides the specimens enumerated by Davidson I have eight from 
Lummaton in my Collection. There are two from Wolborough in Mr. Vicary’s 
Collection, and one from Lummaton in the British Museum. 
1 1879, Barrande, ‘Syst. Sil. Bohém.,’ vol. v, pl. lxxxiii, figs. 6 a—f, Et. F. 
2 From évavrios, reversed ; and o¢jv, a wedge. 
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