BRACHIOPODA. 
163 
imbricating concentric lines. The structure of the cardinal process differs in 
some respects from that of Atrypa reticularis, being much more like that of 
Zygospira modesta ; while, in regard to the brachial apparatus, the coiling of 
the spirals is lax, the cones themselves introverted more as in Zygospira 
than in Atrypa, and the loop, though posterior in position, is apparently con¬ 
tinuous and acutely angled as in Catazyga. 
To this group may be applied the foregoing term, Atrypina, a name suggest¬ 
ing the affinities of the fossils. 
Genus ATRYPA, Dalman. 1828. 
PLATE LIV. 
1767. Anomia, Linne. Systema Naturae, ed. xii, p. 1152. 
1820. Terebratulites, Schlotheim. Petrefactenkunde, p. 262, Nachtr., pi. xvii, fig. 2; pi. xviii, fig. 2 ; 
pi. XX, fig. 4. 
1821. Anomites, Wahlenberg. Nov. Act. Reg. Soc. Scientif. Upsal., vol. viii, p. 65. 
1822. Terebratula, Sowerby. Mineral Conchology, vol. iv, p. 324, fig. 2. 
1828. Atrypa, Terebratula, Dalman. Kongl. Vetenskaps. Akad. Handlingar, pp. 127, 128, 143, pi. iv, 
figs. 2, 3 ; pi. vi, fig. 6. 
1837. Atrypa, Terebratula, Hisingbr. Lethaea Suecica, pp. 75, 81, pi. xxi, figs. 11 a-e; pi. xxiii, 
figs. 8 a-c. 
1842. Atrypa, Conrad. Jour. Acad. Nat. Sci. Philadelphia, vol. viii, p. 265. 
1842. Atruva, Hipparionyz, Vandxbm. Geology of N. Y.; Rept. Third Dist., p. 88, fig. 12 : p. 132, 
fig. 2 ; p. 139, fig. 5; p. 163, fig. 3; pp. 164, 182, fig. 4. 
1843. Tertbratula, Castelnau. Essai sur le Systeme Silurien, 40, pi. xiii, fig. 8. 
1843. Atrypa, Hall. Geology of N. Y.; Rept. Fourth Dist., p. 73, fig. 8; p. 108, fig. 37 ; p. 175, fig. 5; 
p. 198, tig. 4 ; p. 200, figs. 1, 2 ; p. 215, fig. 3 ; p. 271, figs. 1-3 ; Tab. of Org. 
Rem., No. 13, fig. 1. 
1844. Atrypa, Owen. Geol. Expl. of Iowa, Wisconsin and Illinois, pi. xii, figs. 2, 10. 
1847. Splrige^’ina, d'Orbigny. Comptes rendus, vol. xxv, p. 268. 
1847. Terebratula, Yandell and Shumard. Contribution to the Geol. of Kentucky, p. 10. 
1849. Terebi-atula, Hall. American Journal of Science, vol. xx, p. 227. 
1862. Atrypa, Hall. Palaeontology of N. Y., vol. ii, pp. 72, 79, 270-272, pi. xx, fig. 10 ; pi. xxiii, fig. 8; 
pi. iv, tig. 5 ; xd. Ivi, figs. 1, 2. 
1852. Rhynchonella, Salter. Sutherland’s Jour, of a Voyage in Baffin’s Bay, etc., vol. ii, p. 221, x:)l. v, 
figs. 1-3, 5. 
1854. Atrypa, Davidson. Introd. British Fossil Brachiopoda, xi. 90, x^b vii, figs. 87-94. 
1856. Atrypa, Billings. Canadian Nat. Geol., vol. i, px). 134, 137, 474, pi. ii, tig. 10; pi. vii, fig. 11. 
1857. Atrypa, Hall. Tenth Rex^t. N. Y. State Cab. Nat. Hist., x^- 122, figs. 1-7; x’- 168. 
1858. Atrypa, Rogers. Geology of Pennsylvania, vol. ii, xia>‘t ii» p- 828, fig. 671 ; p. 829, fig. 681. 
1858. Atrypa, Hall. Geol. of Iowa, vol. i, x>art ii, i3. 515, i^l. vi. tig. 3. 
1859. Atrypa, Hall. Palaeontology of N. Y., vol. iii, x^- 253, pi. xlii, fig. 1. 
1860. Atrypa, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 84. 
1860. Ati'ypa, Robmer. Die Silurische Fauna der westlichen Tennessee, p. 69, pi. v, figs. 9, 10. 
1860. Trematospira, McChesney. New Palaeozoic Fossils, x^. 71. 
1861. Atrypa, Billings. Canadian Journal, vol. vi, p. 264, figs. 84-87. 
