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PALAEONTOLOGY OF NEW YORK. 
not the Orbicula Norvegica of Lamarck,* * * § the Lamarckian species having proven 
identical with the Patella anomala of MuLLER.f This latter species, however, is a 
Crania; and as the 0. Norvegica, Lamarck, was taken as the type-species of 
Cuvier’s genus Orbicula, the genus Orbicula, in its Cuvierian sense, becomes 
a synonym for Crania. This fact of synonymy was pointed' out by Dr. J. E. 
Gray, as long ago as 1825,J but the. genus Orbicula had become so thoroughly 
confounded by authors with Discina that, to avoid a disturbance of nomenclature, 
the name was retained by Mr. Davidson§ and Professor Hall,|| as late as 1852, 
for the Discina of authors, not of Lamarck. 
In 1854, Mr. Davidson^ considered the Discina ostrceoides , Lamarck, as iden¬ 
tical with D. lamellosa, Broderip, 1833,** and therefore, in the absence of a 
description of D. ostrceoides, assumed the latter as the type-species. This assump¬ 
tion must now be regarded as inadmissible, and was abandoned by Mr. Davidson 
in his “General Summary” (1884) and “Monograph of Recent Brachiopoda” 
(1888).ff In accordance with Dall’s observations, we are compelled to accept Dis¬ 
cina striata, Schumacher {Crania striata, Schumacher, Essai d’un nouveau systeme 
des habitudes des Yers Testaces, p. 102, pi. xx, figs. 1 a-f, 1817, = Orbicula 
Norvegica, Sowerby, 1822, not Lamarck, 1801, = Discina ostrceoides, Lamarck, 
1810), as the typical species of the genus. . This species is not to be confounded 
with the Discina striata, Sowerby,^ which is a Silurian (Ludlow) form, while 
Schumacher’s species, the designation of which antedates that of Sowerby, is 
recent and of West African habitat. 
The diagnosis of the genus Discina, as derived from the species D. striata, 
Schumacher, is given by Dall in the following terms: 
“ Sub-genus Discina (Lam.), Dall. Shell of rather solid texture, with a con- 
* Syst. Nat., p. 140. 1801 ; and Hist. Animaux sans vert&b., Ed. I, vol. vi, p. 242. 1819; Ed. II, vol. 
vii, p. 316. 1836. 
t Zoologiae Danicae Prodromus, p. 237. 1776. 
J Annals of Philosophy, New Series, vol. x, p. 244. 
§ Tertiary Brachiopoda. 
| Palaeontology N. Y., vol. ii. 
Introd. Brit. Foss. Brach. 
** Proc. Zool. Soc., vol. i, pp. 124, 125. 
ft Trans. Linnean Society, Second Series, Zoology, vol. iv, pt. 3. 
It Sil. Syst., pi. v, fig. 21. 1839, and Davidson, Silur. Brach., p. 67, pi. vi. figs. 1-4. 
