Spirifer. 
MOLLUSCA. 
109 
three central ones thicker and more elevated than the others, 
and obscurely divided, the central into three and the others 
into two; back or lower valve flat, meeting the sides at an 
acute angle; whole surface with fine, sharp, elevated, rather 
distant, transverse strife. 
Figs. 3 and 4 represent the internal spiral appendages, from whence 
the name of this genus is derived. 
Carboniferous Limestone, Derbyshire; and the Mountain 
Limestone in many localities. 
Section II.— Angustalje —Cardinal line as wide as 
the shell; valves with incurved umbones; mesial fold 
defined between two deeper furrows on the upper valve. 
12. Spirifer pyramidalis —The Pyramidal Spirifer, pi. 
LI. fig. 7. 
Spirifera triangularis. Phillips, II. p. 217, pi. 9, fig. 12. 
Triangularly pyramidal; mesial fold narrow; umbo of lower 
valve greatly produced, and infiected ; lower sides of the valves 
acutely triangular, ending in a sharp base; surface with from 
seventeen to nineteen longitudinal, divergent, rather flattened 
ribs, the central one considerably thicker than the others, the 
lateral ones few in number. 
Mountain Limestone at Bolland, Kirby Lonsdale, and Der¬ 
byshire. 
13. Spirifer rotundatus.— The Rounded Spirifer, pi. 
L. fig. 17, 18. 
Spirifer rotundatus. Sowerby, V. p. 89, pi. 461, fig. 1, 1. 
Globose, transversely ubovate; cardinal area triangular, of 
medium length, and not so long as the sides; beaks incurved, 
and approximating, that of the lower valve pretty large; middle 
of the upper valve with a smooth, elevated ridge; whole surface 
with rather depressed, longitudinal, divergent ribs, crossed at 
intervals by nearly obsolete lines of growth; cavity of the lower 
valve with some obscure, longitudinal lines, but destitute of a 
central division ; margins of the valves very sharp. 
Found in the Black Limestone at Limerick, Ireland. 
14. Spirifer Beanii. —Bean’s Spirifer, pi. L. fig. 8. 
Spirifera rotundata. Phillips, II. p. 218, pi. 9, fig. 17* 
Beaks somewhat approximate; cardinal area rather con¬ 
tracted ; hinge line quite parallel, angular at the extremities; 
the sides bulging considerably from below the angles ; whole 
surface with strong, radiating sulci ; mesial fold broad, nearly 
smooth. 
Distinguished from S. rotundatus by the cardinal area being narrower, 
and its extremities more acute. 
Mountain Limestone, Kildare, Bolland, and Queen’s County. 
15. Spirifer octoplicatus. —The Eight-plaited Spirifer, 
pi. L. fig. 9, 10. 
Spirifer octojjlicatus. Sowerby, VI. p. 120, pi. 562, fig. 
2, 3, 4. 
Transversely elongated, semicircular, inflated; beaks remote; 
cardinal area wide, curved, and triangular, with from eight to ten 
deep, angular, longitudinal ribs or plaits, producing a strongly 
crenulatcd margin ; mesial fold plain. 
The Mountain Limestone, Derbyshire. 
16. Spirifer pinguis. —The Plump Spirifer, pi. L. fig. 
13, 14. 
Spirifer pinguis. Sowerby, III. p. 125, pi. 271. Fleming, 
p. 375. 
Gibbose, nearly globular, slightly transversely obovate; beaks 
rather close; cardinal area shallow, not so wide as the shell; 
with eight or nine rounded, longitudinal ribs on each side of 
the mesial fold ; groove in the lower side corresponding to the 
mesial fold, but not sulcated; intervening furrows rounded at 
bottom. 
Black Rock Limestone of Ireland. 
17. Spirifer Walcottii. —Walcott’s Spirifer, pi. L. fig. 
11 , 12 . 
Spirifer Walcottii. Sowerby, IV. p. 106, pi. 377, fig. 2. 
Suborbicular, both valves gibbose, smooth; cardinal area tri¬ 
angular, shorter than the width of the valves; umbo of the 
larger valve pointed and incurved; both beaks provided with 
an angular foramen; mesial fold wide, rounded, with four rather 
elevated, rounded, longitudinal ribs on each side. 
Found in the Lias at Camerton. 
18. Spirifer minimus —The Least Spirifer, pi. L. fig. 
15, 16. 
Spirifer minimus. Sowerby, IV. p. 105, pi. 377, fig. 1. 
Transversely oblong, inflated, smooth, and subrhomboidal; 
umbones produced, and rather acute at the points; cardinal area 
long, flat; foramen between the umbones an elongated triangle; 
surface with fifteen flat, longitudinal ridges, the three central 
ones more elevated than the others, and but ill defined. 
Found in the Mountain Limestone near Bakewell, Derby¬ 
shire. 
19. Spirifer striatus —The Striated Spirifer, pi. L. fig. 
19 , 20 . 
Spirifer striatus. Sowerby, III. p. 125, pi. 270. Anomites 
striata, Martin, Pet. Derb. pi. 23. Terebratula striata , Sower¬ 
by, Linn. Trans. XII. p. 515, pi. 28, fig. 1, 2. Fleming, 
p. 375. 
Transversely elongated, subcompressed ; cardinal area wide, 
shallow, long, smooth, slightly striated, and acute at the sides; 
mesial sinus angular ; beaks of moderate length, and incurved ; 
whole surface with numerous, longitudinal, narrow, irregular 
ribs, and inequidistant lines of growth. 
The Mountain Limestone of Derbyshire and Cork. 
20. Spirifer bisulcatus. —The Two-furrowed Spirifer, 
pi. L. fig. 21, 22. 
Spirifer bisulcatus. Sowerby, V. p. 152, pi. 494, fig. 1, 2. 
Fleming, p. 375. 
Gibbous, semicircular, its width but slightly exceeding its 
length; cardinal area long, straight, with parallel sides, caused 
by the edges of it upon the deeper valve being reflected: beaks 
rather prominent, curved, and nearly meeting; a deep furrow 
on each side of the mesial ridge; the whole surface with about 
thirty rather regular, longitudinal ribs, two on each side, near 
the centre, considerably deeper than the others, with the 
intervening spaces frequently convex, although they are flat in 
some. 
Carboniferous Limestone, neighbourhood of Dublin. 
21. Spirifer attenuatus _The Attenuated Spirifer, pi. 
L. fig. 25, 26. 
Spjirifer attenuatus. Sowerby, V. p. 151, pi. 493, fig. 3, 4, 
5. Fleming, p. 375. 
Convex, transversely elongated, its breadth more than double 
its length ; cardinal area long, straight, with nearly parallel 
edges; sides produced, and acute; beaks short, and but little 
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