Modiola. 
CONCHIFERA. 
posterior section of the shell; rounded and narrowed anterior¬ 
ly ; expanded posteriorly, with an oblique curved truncation. 
The Silurian Rocks, Tyrone, Ireland. 
42. Modiola skcuriformis. — The Axe-shaped Modiola. 
A. sec ur if or mis. Portlock, Coo. Sur. p. 42.5, pi. 33, f. 8. 
Elongated ; anterior side narrowed and rounded ; posterior 
side expanded and rounded, but destitute of the oblique trun¬ 
cation ; an oblique ridge oxtends from the beak to the poste¬ 
rior margin. 
The Silurian Rocks, Tyrone, Ireland. 
43. Modiola Brycei. —Bryce’s Modiola. 
M. Brycei. Portlock, Geo. Rep. p. 425, pi. 33, fig. 7. 
Attenuated and rounded auteriorly ; hinge-line rather ex¬ 
tended ; the diagonal ridge strongly marked ; surface smooth, 
with faint-lines of growth. 
The Silurian Rocks, Tyrone, Ireland. 
44. Modiola carinata. — The Keeled Modiola, pi. LXI.*** 
figs. 10, 20. 
M. carinata . Sowerby, Geo. Tr. 2d Ser. V. pi. 30, fig. 15. 
Obliquely elongated, ventricose, boat-shaped ; valves deep ; 
anterior side short; posterior side lengthened ; beaks obtuse ; 
an abrupt carinated ridge extending from the beaks to the 
posterior lower angle of the valves; surface with a few obso¬ 
lete lines of growth. 
The Coal Measures, Coalbrook Dale. 
45. Modiola Macadami.— Macadam’s Modiola,pi. LXI.*** 
figs. 14, 15, 16. 
M. Macadami. Portlock, Geo. Rep. p. 432, pi. 34, figs. 
13, 14, 15. 
Variety 1. — Augusta, pi. LXI.*** fig. 14. -Portk. pi. 34, fig. 13. 
Lengthened, narrow, convex, somewhat cylindrical, but 
wider behind than before; beaks obscure, situate very near 
the anterior side ; front rounded, and with a slight obliquity 
in the posterior margin; binge-line straight, but not distinct; 
surface with fine concentric striae. 
u This diverges as much from the ordinary form in one direction as 
fig. 15 does in another.”— Portlock . 
Variety 2 .—Elongata, pi. LXI.*** fig. 15--Portk. pi. 34, fig. 14. 
Elongated ; narrowed at both extremities; beaks quite de¬ 
pressed ; hinge-line straight, oblique, terminating in an angle, 
and equal to about half the length of the shell; from thence 
the side gradually slopes downwards; surface with fine raised 
thread-like striae. 
“ This approximates to Modiola lingualis (Phillips.)”— Portlock. 
Variety 3 .—Lata, pi. LXI.*** fig. 1G.-Portk. pi. 34, fig. 15. 
Ovate; beaks obsolete ; hinge-line straight, and exceeding 
one-half the length of the shells, and terminating in an angle ; 
anterior side extremely short and rounded ; posterior side ex¬ 
panded and compressed ; surface wrinkled on the anterior side 
and at the beaks, and exhibiting the appearance of the shell 
having been originally covered with concentric thread-like 
raised strke. 
“ The flattened form is probably the result of pressure, as it is rare ; 
and the ordinary form exhibits a more distinct rise, or rounded ridge, 
from the beak to the posterior margin, and is narrower.’*-— Portlock. 
The Carboniferous Limestone, Ballynascreon, Derry and 
Tyrone. 
If form goes for anything, the three varieties of this shell would appear 
to be distinct; and looking at the lines of growth on figs. 14 &. 15, we 
cannot see how they could a sme the form of fig. 16. 
175 
40. Modiola granulosa.— The Granular Modiola. 
M. granulosa. Phillips, Geo. York, II. p. 210, pi. 5, f. 23. 
“Very much elongated, depressed; surface granulose.”— 
Phillips. 
The Carboniferous Limestone, Holland and Northumber¬ 
land. 
47. Modiola Nerei. —Xores Modiola, pi. LXI.*** f. 17. 
M. Nerei. My til is (?) Nerei. Munster, Beit. 1840, pi. 11, 
fig. 14; Portlock, Geo. Rep. p. 424, pi. 33, fig. 10. 
Obovate, convex, thick ; beaks terminal, a little produced ; 
sides almost equal, curved, and the basal extremity rounded ; 
binge-line straight ; surface with fine regular concentric stria*. 
The Silurian Rocks, Dcsertcreat, Tyrone, Ireland. 
48. Modiola marmorata. —The Marbled Modiola. 
M. marmorata. Brown, Recent Conch. Brit. & Ir. p. 78, 
pi. 27, fig. 10. M. discors. Tin-ton, p. 210, pi. 15. figs. 4, 5. 
Oval, very tumid; anterior side a little pointed; beaks 
terminal, rounded, and somewhat convolute; centre of the 
valves a little constricted towards the margin; surface smooth, 
with a series of longitudinal divergent grooves at both sides, 
and slightly striated transversely at the pointed extremity. 
The Pleistocene Marine Formation, Ayrshire, and the 
Coral Crag, Sutton. 
40. Modiola sub-parallel a. —The Sub-parallel Modiola, 
pi. LXI.*** fig. 18. 
M. sub-parallel a. Portlock, Geo. Rep. p. 433, pi. 34, f. 1G. 
Oblong-ovate; convex; beaks obtuse ; hinge-line long and 
nearly straight; anterior side short, the posteifbr long; both 
extremities almost equally rounded ; with a slight contraction 
from the beaks to the margin, forming an obscure anterior lobe; 
a diagonal rise from the beak to the margin, not constituting 
a ridge; surface with somewhat irregular thread-liko con¬ 
centric strke. 
The Carboniferous Limestone, Ballynascreen, Tyrone, Ire¬ 
land. 
50. Modiola scalaris. —The Ladder Modiola. 
M. scalaris . Phillips, Pal. Fos. p. 137, pi. 60, fig. 02.* 
“ Depressed, transversely elongated to a parallclogramic 
figure, with elliptical terminations; front edge straightened, 
or slightly sub-concave near the middle; surface ridged by 
about fifteen elevated narrow threads, parallel to the margin, 
separated by wider flat spaces, in which are fine strke parallel 
to the elevated threads.'*— Phillips. 
Devonian Shales, Berry Pomeroy, South Devon. 
51. Modiola papuana.— The Common Modiola. 
M. papuana. Brown, lllust. Rcc. Conch. Blit. p. 77, pi. 
27, figs. 1, 2, 3, 4, 5, G. 
Transversely oblong; anterior side short; posterior side 
lengthened, dilated, and rounded; beaks tumid and obtusely 
angular; surface smooth. 
The Mammiferous Crag, Postwick. 
52. Modiola acuminata.— Soicerby, Geo. Tr. 2d Ser. 
III. p.lJ9.— Not described. 
The Magnesian Limestone, Humbleton, Durham. 
53. Modiola decussata. —The Decussated Modiola, pi. 
LXI.*** figs. 22, 23. 
M. (?) Jelly, Mag. Nat. Hist. III. New Ser. p. 551, fig. 
69. 1. c . 
