BRACHIOPODA. 205 



Conrad.* The former has a very considerable range, appearing, according to 

 DavidsonI in the Caradoc, Lower and Upper Llandovery, Woolhope, Wenlock 

 and Ludlow formations. 



In America it has been found only in the Niagara group, while its congener, 

 Orlhis varica, Conrad, a very distinct species,^: is confined to the Lower Helder- 

 berg fauna. 



DALMANELLA 



(nom, i3ropos). 



X. Group of Orthis testudinaria, Dalman. 



PLATE Ve, figs. 25-39; AND PLATE Vc, FIGS. 1-47. 



1828. OrtM.1, Dalman. Kong-1. Vet.. Acad. Handl., pp. 115, 117, pi. ii, tig. 4. 



1842. Ovthis, Emmons. Geology of N. Y. ; Rept. Second Dist., p. 404, fig. 4. 



1842. OrtUs, Vanxixem. Geology of N. Y. ; Rept. Third Dist., p. 139, tig. 4. 



1843. OHMs, Atrypa? Hall. Geology of N. Y. ; Rept. Fourth Dist., p. 10.o, tig. 6; p. 175, fig. 4, and 



p. 271, fig. 4. 

 1543. Orthis, Conrad. Proc. Acad. Nat. Sci., Phila., vol. i, p. 133. 

 1847. OrtMs, Hall. Palceontology of N. Y., vol. i, pp. 117, 118, 120, 128, pi. xxxii, figs. 1, 2, 5, and pi. 



Ixxix, fig. 4. 

 1852. Orthis, Hall. Palieontology of N. Y., vol. ii, p. 152, pl. lii, tig. 3. 



1856. OrtUs, Billinss. Canadian Nat. and Geol., vol. i. p. 40, tig. 1, and p. 136, pl. 2, fig. 5. 



1857. Orthvi, Billings. Rept. of Progress Geol. Surv. Canada for 1856, p. 296. 



1857. OrtMs, Hall. Tenth Rept. N. Y. State Cab. Nat. Hist., p. 42, figs. 1, 2, and p. 44, fig. 1. 



1859. Orthis, Hall. Paljeontology of N. Y., vol. iii, pp. 168-172, pl. xii, figs. 1-21, and pl. xiii, figs. 1-12. 



1859. Orthis, Billings. Canadian Nat. and Geol., vol. iv, p. 434, fig. 10. 



1860. Orthis, F. Roemer. Sil. Fauna westl. Tennessee, p. 62, pl. v, tig. 7. 

 1860. Orthis, Hall. Thirteenth Rept. N. Y. State Cab. Nat. Hist., p. 121. 

 1862. Orthis, Hall. Geology of Wisconsin, vol. i, p. 42, fig. 7 and p. 436. 

 1862. Orthis, Billings. Paleozoic Fossils, vol. i, p. 79, fig. 72. 



1862. Orthis, Hall. Fifteenth Rept. N. Y. State Cab. Nat. Hist., pl. ii, figs. 1-3. 



1863. Orthis, Billings. Geology of Canada, pp. 130, 165, 231, 312, figs. 57, 144, 246, 320. 



1867, Orthis, Hall. Palieontology of N. Y., vol. iv, p. 35, 46, 62, pl. v, figs. 1, 2; pl. vi, fig. 1 and 



pl. viii, figs. 3-8. 



1868. Orthis, Meek and Woethen. Geology of Illinois, vol. iii, p. 373, pl. vii, fig. 6. 



1873. Orthis, Meek. Paleontology of Ohio, vol. i, pp. 103, 109, 112, pl. viii, figs. 1-3, 5. 



1874. Otthis, James. Cincinnati Quart. Jour. Sci., vol. i, p. 19. 



1875. OHhis, Miller. Cincinnati Quart. Jour. Sci., vol. ii, pp. 20, 22, 24, 30. 



* The Orthis acutiloba of Ringuebeeg is a form of 0. hiloha in which the lobes are very divergent. AU 

 stages of variation between this extreme and the normal form for the species are readily detected in any 

 large collection. 



t British Silurian Brachiopoda, p. 208. 



I Davidson (Silurian Brachiopoda, p. 207) and Qubnstedt (Petrefactenkunde Deutschlands, pl. Iv, figs. 

 67-70), erroneously regarded this species as indentical with 0. hiloba. 



