500 BRITISH PALAXOZOIC FOSSILS. [ LaMELLIBRANCHIATA. 
EpMoNDIA comMpREssA (J/‘Coy). 
Ref.—M Coy, Syn. Carb. Foss. Irel. t. 13. f. 10. 
Dese.—Ovato-oblong, beaks rather tumid, small, rounded, oblique, close to the anterior end; anterior end 
very short, rounded; ventral margin moderately convex ; dorsal margin nearly straight ; posterior end slightly 
narrowed, obtusely rounded; no posterior slope nor-diagonal gibbosity; valves evenly and gently convex, most 
so near the beaks about half-way between them and the ventral margin, from thence arching abruptly to the 
anterior edge, and more gently towards the ventral, dorsal, and posterior edges; anterior lunette beneath the 
beaks small, deep, rounded’; surface smooth or marked with a few small, obsolete, concentric wrinkles of growth. 
Length about two inches three lines, proportional width from beak to ventral margin jj, width of posterior 
end +3, length of anterior lunette ;7;, depth of one valve =. 
Some of the above measurements are taken from the original Irish specimen, the English one in the col- 
lection being imperfect ; the latter however shews the thick internal cartilage ridge, beneath the simple erect 
dorsal margin, of Hdmondia. 
Position and Locality.—Rare in the lower carboniferous limestone of Isle of Man. 
Epmonp1a Eqertoni (M°Coy). 
Ref. and Syn. = Cyprina Egertoni M°Coy, Syn. Carb. Foss. Trel. t. 10. f. 9. 
Desc.—Quadrato-orbicular, moderately and evenly convex; beaks large, tumid, obliquely inclined to the 
very large, deep, ovate, anterior lunette ; hinge-line short, gradually rounded into the rotundato-quadrate pos- 
terior end; anterior end large, semicircularly rounded, broad; ventral margin evenly convex; substance of the 
shell very thick ; surface concentrically grooved by slightly irregular, subequal, obtuse, cord-like ridges (averaging 
seven in two lines at an inch and half from the beak). Length of small specimen two inches two lines, propor- 
tional width from beak to ventral margin =, length of anterior end =;, length of anterior lunette 3, width 
thereof /2, depth of one valve (greatest at one-third from the beak) =; (adult specimens three inches nine lines 
long), thickness of the shell rather more than one line. 
The nearly orbicular form, close, cord-like concentric ridging, subcentral beaks, and large size, easily dis- 
tinguish this from other species of the genus, giving it much the external appearance of Cyprina. Casts 
shew the very large anterior and posterior adductor impressions strongly marked when the shell is entirely 
removed, connected by the strong, simple, pallial scar, also the thick cartilage ridge beneath the hinge-margin on 
the posterior side, and bordering the edge of the lunette on the anterior one. A few elongate points or scratch- 
like markings, arranged in regular radiating lines, are seen with a glass on most of the specimens of internal 
casts. 
Position and Locality—Not very common in the impure carboniferous limestone of Lowick, Northum- 
berland. 
Epmonpia JosepHa (de Kon.) 
Ref—de Kon. Anim. Foss. Bel. t. 1. f. 5. 
Desc—Oblong, moderately compressed ; beaks rather large, oblique, compressed, approximate, close to the 
anterior end, which is very short, subtruncate, rounded; posterior end slightly narrowed, subtruncate, obtuse, 
rounded; ventral margin very slightly convex ; hinge-line nearly as long as the shell; anterior lunette small, 
ovate; valves rather flattened, moderately and evenly convex, most so at about one-third the width from the 
beaks, gradually arching from thence to the ventral and posterior margins, abruptly sloped to the anterior end, and 
abruptly rounded to the cardinal margin, but no posterior slope or diagonal ridge ; surface with numerous sub- 
regular, obtuse, concentric wrinkles (about three or four in two lines near the margin), and coarse strize of growth. 
Length ten lines; in proportion thereto greatest width (from beak to ventral margin) 7, width of posterior end 
55 15 50 
=» length of anterior end ;;, length of anterior lunette ;4, depth of both valves 3. 
