192 PALEONTOLOGY OF NEW YORK. 



Trenton, and 0. Davidsoni, de Verneuil (0. calligramma, var., according to 

 Davidson*), of the Niagara. 



Mr. Davidson was disposed to regard the Swedish specimens of 0. calladis as 

 showing but varietal differences from 0. calligramma, and his use of these two 

 terms, the former subordinate to the latter, should strictly be reversed. Orthis 

 calladis may, therefore, properly be taken as the tj^pical form of the genus in 

 its restricted construction, and upon the diagnosis above given it will be neces- 

 sary to exclude the remainder of Dalman's species, with the exception of 0. 

 demissa, as it will be shown that 0. testudinaria, 0. basalis and 0. ekgantula be- 

 long to a distinct type of structure.! 



ORTHIS, Dalman, as restricted. 

 I. Group of Orthis callactis, Dalman. 1828. 



PLATE V, FIGS. 1-17, 37-41. 



1828. Orthis, Dalman. Kongl. Vet. Acad. Handl., pp. 93, 96. 



1830. Orthamhonites, Pander. Beiti-. zur geognos. des rus.sisch. Reiches, p. 80, pi. iii, fig. 7 ; p\. xxviii, 



fig. 18. 



1839. Orthis, Sowbrby. Murchison's Silui-ian Syst., p. 639, pi. xxi, fig. 8. 



1843. Orthis, Hall. Geology N. Y. ; Rept. Second Dist., p. 105, fig. 5. 



1843. Orthis, Conrad. Proc. Acad. Nat. Sci., Philadelphia, vol. i, p. 333. 



1844. Orthis, Owen. Geol. Expl. lowa.Wisconsin and Illinois, pi. xv, fig. 11. 



1847. Orthis, Hall. Paleontology N. Y., vol. i, p. 20, pi. iv bis, fig. 4 ; pp. 119, 121, pi. 32. 



1852. OrUm, Hall. Paleontology of N. Y., vol. ii, pp. 254, 255, pi. lii, figs. 6, 7. 



1856. Orthis, Billing.s. Canadian Nat. and Geol., vol. i, p. 136, pi. ii, fig. 6. 



1859. Orthis, Billings. Canadian Nat. and Geol., vol. iv, p. 440, fig. 20. 



1859. Orthis, Salter. Canadian Organic Remains, Decade i, p. 39, pi. ix, figs. 1-4. 



1862. Orthis, Billinss. Paleozoic Fossils, vol. i, p. 77, fig. 70 ; p. 78, fig. 71; p. 81, fig. 73. 



1862. Ort?ns, Hall. Geology of Wisconsin, vol. i, p. 42, figs. S-11 ; p. 435. 



1863. OrtJds, Billings. Geology of Canada, p. 130, fig. 60 ; p. 167, fig. 151 ; p. 231, fig. 245 ; p. 312, 



fig. 318. 

 1865. Orthis, Shaler. Bulletin No. 4, Mas. Comparative Zool., p. 66. 

 1875. Orthis, Nicholson. Paleontology Province Ontario, p. 47, fig. 21. 

 1875. Orthis, White. Geogr. and Geol. Expl. west 100th Merid., p. 72, pi. iv., fig. 10. 

 1883. OHJiis, Hall. Rept. N. Y. State Geologist for 1882, pi. xxxiv, fijjs. 35-38, 41, 42 and pi. xxxv, 

 figs. 1-8. 



* British Silurian Brachiopoda, p. 244. 



t Dalman's paper of 1828 has become so rare as to be beyond the ]'each of most Amei-ican students. 

 We have, therefore, reproduced by photo-engraving the fii-st two plates of this work with the pi-ecise form 

 and arrangement of the original, and they will be found inserted at the end of these discussions, and pre- 

 ceding the lithographic plates. These plates are Tab. I and II of the Kong. Vetenskaps-Academiens 

 Handlingar for ar 1827, and bear all of the author's figures of the species of Orthis as well as those of his 

 genus LEPTa;NA. 



