no 
MOLLUSCA. 
Spirifer. 
elevated above the hinge line; front rounded, with an elevated 
mesial fold, on each side of which is a deep furrow; whole 
surface covered with numerous, linear furrows, which increase 
in number towards the margin, the spaces between the furrows 
in the form of thin branched ribs. 
The Carboniferous Limestone near Dublin. 
22 . Spirifer undulatus _The Waved Spirifer, pi. L. 
fig. 27, 28. 
Spirifer undulatus . Sowerby, VI. p. 119, ph 562, fig. 1. 
Convex, transversely elongated, its width being twice its 
length ; cardinal area Hat, rather narrow, with almost parallel 
edges, and acute at the extremities; beaks approximate, and 
not much elevated; mesial elevation rather inflated, and round¬ 
ed ; whole surface with numerous, well defined, longitudinal 
ribs, sixteen on each side of the mesial sinus, crossed by deep, 
wide-set, regular stria?, which are semicircular in passing over 
the ribs. 
From the Magnesian Limestone at East Thickly, West Auk- 
land, County of Durham. 
23. Spirifer semicircularis —The Semicircular Spirifer, 
pi. L. fig. 23, 24. 
Spirifer semicircularis . Phillips, II. p. 217, ph 9, fig* 15, 16 . 
Upper valve nearly semicircular; cardinal area variable in 
width, sharp at the extremities ; beaks rather obtuse ; mesial 
fold very broad, and sulcated ; surface with smooth, radiating, 
longitudinal ribs, fifteen or sixteen on each side of the mesial 
fold, and divarigated at their base. 
Suliject to a little variety; some with the cardinal area rectangular, 
and others acute. 
Mountain Limestone at Chipping; Whitewell, Queen’s Coun¬ 
ty, Ireland; and Isle of Man. 
24. Spirifer plicatus —The Plaited Spirifer, pi. LII.* 
fig. 1 . 
Spirifer plicatus . Murchison, p. 638, pi. 21 , fig. 6 . 
Semicircular, convex; cardinal area long, narrow, extending 
to nearly double the length of the shell; whole surface with 
wide-set, divergent plaits ; beaks approximate. Length eleven 
lines; breadth one inch and seven lines. 
Cardoc Sandstone, Goleugoed and Llandovery, Wales. 
25. Spirifer alatus. —The Winged Spirifer, pi. LII.* 
fiir. 3, 4. 
Spirifer alatus . Murchison, p. 638, pi. 22 , fig. 7. 
Semicircular j cardinal area long, narrow, terminating in con¬ 
siderably expanded, cuspidate sides 5 centre of the valves a little 
inflated ; whole surface with about eighteen acute plaits. 
Length five lines and a half; width nine lines and a half. 
Cardoc Sandstone, Pensarn and Mount Pleasant, Caermar- 
then. 
26. Spirifer pinnatus. —The Pointed Spirifer, pi. LII.* 
fig. 4, 5. 
Spirifer alatus. Murchison, pi. 22, fig. 7, the low r er figs. 
Transverse, oblique, somewhat semicircular ; hinge line 
straight, very narrow, and prolonged to an acute point at both 
sides, one side more lengthened than the other ; beaks a little 
elevated ; surface with numerous, divergent plaits. 
This diiTers from S. alatus , in being much longer in proportion to its 
breadth, and in being a little oblique, with one wing longer and more 
acute than the other. 
Cardoc Sandstone, Mount Pleasant, Caermarthen, 
27. Spirifer iiumerosa —The Hooded Spirifer, pi. LI. 
fig. 3 . 
Spirifera Iiumerosa. Phillips, II. p. 218, pi. 11, fig. 8. 
Subcordiform ; lower valve very large, and very turgid near 
the umbones, with a produced mesial fold, which receives the 
angular and elevated ridge of the upper valve ; surface with 
numerous, small, longitudinal, divergent ribs. 
Mountain Limestone, Grecnhow Hill, Yorkshire. 
Section III—Radiatje.—C ardinal area not so wide 
as the shell; surface radiated. 
28. Spirifer lineatus —The Lineated Spirifer, pi. L. 
fig. 6, 7* 
Spirifer lineatus. Sowerby, V. p. 151, pi. 493, fig. 1, 2. 
Fleming, p. 375. 
Gibbose • umbones produced, somewhat remote, with their 
beaks approximate; cardinal area long, rounded, rather narrow, 
and with a triangular foramen; front semicircular, with a pretty 
elevated, mesial fold, ending in the beak; whole surface with 
numerous, divergent, sharp, granulated stria?. Breadth some¬ 
what more than its length. 
Dudley Limestone at Dudley. 
29. Spirifer ovalis —The Oval Spirifer, pi. LI. fig. I. 
Spirifera ovalis. Phillips, II. p. 219, ph 10, fig. 5. 
Elliptical; cardinal area triangular; umbones produced, in¬ 
curved ; mesial fold large, obtusely rounded, spreading widely at 
the base; with six or seven pretty broad ribs on each side. 
Mountain Limestone, Bolland. 
30. Spirifer planata. —The Plane Spirifer, pi. LI. fig. 6. 
Spirifera planata. Phillips, II. p. 219, pi. 10, fig. 3. 
Suborbicular; cardinal area rather wide; umbones obtuse, 
and remote; surface with numerous, flat, plain ribs; upper 
valve nearly plane. 
Mountain Limestone, Bolland. 
31. Spirifer trisulcosa —The Three-furrowed Spirifer, 
pi. LI. fig. 9. 
Spirifera trisulcosa. Phillips, II. p. 219, ph 10, fig. 6. 
Elongated, rather smooth ; beaks produced; cardinal area 
subtriangular; upper valve with a pretty large, produced, mesial 
fold, and a lateral plait on each side. 
Mountain Limestone, Bolland. 
32. Spirifer integricosta —The Inter-ribbed Spirifer, 
ph LI. fig. 8. 
Spirifera integricosta. Phillips, II. p. 219, ph 10, fig. 2. 
Nearly orbicular, and greatly inflated; umbones large, much 
curved, the beaks nearly meeting; mesial fold of medium size; 
longitudinal ribs few, obtuse, entire, and smooth. 
Mountain Limestone, Bolland and Northumberland. 
33. Spirifer triradialis. —The Three-rayed Spirifer, ph 
LI. fig. 10. 
Spirifera triradialis. Phillips, II. p. 219, ph 10, fig. 7. 
Orbicular, smooth ; beaks of under valve large, incurved ; 
upper valve depressed, with a broad mesial fold and a lateral 
fold on each side. 
Mountain Limestone, Bolland. 
34. Spirifer sexradialis —The Six-rayed Spirifer, pi. 
LI. fig. 17* 
Spirifera sexradialis. Phillips, II. p. 219, ph 10, fig. 8. 
