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SUPPLEMENT TO THE BRITISH 
described them in an nllied Devonian species, Cyriina heterodyki. In 1841 both 
M. Bouchard and myself were well acquainted with the interior characters of the 
ventral valve of the Devonian shell, for we had discovered excellent examples of both 
Cyriina heferoclyta and C. Demarli in the Devonian Limestone of Ferques in the 
Boulonnais, and I was thus enabled many years ago to both describe and illustrate the 
septa and dental plates in this species. I regret having inadvertently omitted to note in 
my Monograph Prof. King's subsequent observations published in the * Annals and Mag. 
of Nat. Hist.,' vol. xviii, p. 68, 184G. Prof. King's discoveries that the shell was 
provided with spirals, and that its shell-structure was traversed by canals, were decided 
additions to our information. 
Prof. L. de Koninck states, in his published memoir already referred to, that Cyrtina 
sejjtosa in Belgium is a species occurring in the Limestone of Vise, and it is found also 
in Derbyshire. 
Genus Athyris, MCoy = Spirigera, dC Orbigny. 
20. Athyris pisum, Bav. Sup., PI. XXX, figs. 15, 15 (S', (5, c. 
Athyris pisum, D«i?., MS„ Armstrong and Young, Catalogue of the Western 
Scottish Fossils, p. 48, 18/6. 
Shell globular and circular, about as wide as long, without fold or sinus in either 
valve; both valves about equally and evenly convex, and covered with fine concentric 
lines. Beak small, and truncated by a small circular foramen lying close under the 
umbo of the dorsal valve. 
Length 2-|-, width 2^, depth 2 lines. 
Ohs. — Eive examples of this small species were found by Mr. James Thomson in 
Carboniferous Shale at Brockley, Lesmahagow, in Scotland, and all agreed in dimensions 
and in external character. The interior is not known. It is also stated to have been 
found in Beith Quarries, Ayrshire. 
Prof, de Koninck observes, in his ' Liste des Brachiopodes Carboniferes de Belgique,' 
1859, that the distribution of the species of Athyris is remarkable ; that A. plano-sulcata 
and A- lamellosa are the only species of which he has been able to establish the simul- 
taneous presence in the limestones of Vise and Tournay ; the first, which is tolerably- 
spread, is indicated to occur in Ireland, Scotland, England, Russia, and Belgium ; the 
second is known only at Bolland, in Yorkshire, at Hook Point, in Ireland, at Vise and 
Tournay, where it is not rare. A. Eoyssii, A. sq_uamiyera^ and A. suhtilita are found 
only in the limestone of Tournay and in its corresponding formation in Great Britain. 
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