BIBLIOGRAPHIC LIST OF GENERA AND SPECIES. 889 



Okthis (Flatystrophia) crassa James. Sec Platystrophia crassa. 



Orthis crispata Emmons. See Hebertella (Glyptorthis) erispata. 



Orthis cyclus James. See Dalmanella emaeerata. 



Orthis (Platystrophia) cypha James. See Platystrophia cypha. 



Orthis davidsoni Verneuil. 



Orthis davidsoni Verneuil, Bull. Soc. Geol. de France, 2d ser., 5, 1848, p. 341, 



pi. 4, fig. 9.— Billings, Geol. Canada, 1863, p. 312, fig. 318.— Hall and Clarke, 



Pal. New York, 8, pt. 1, 1892, pp. 192, 193, 221, 228, pi. 5, figs. 5-8.— Lesley, 



Geol. Surv. Pennsylvania, Rep. P 4, 1889, p. 512, figs. 

 Orthis calligramma var. davidsoni Nicholson and Hinde, Canadian Jour., n. s., 



14, 1874, p. 144.— Nicholson, Pal. Prov. Ontario, 1875, p. 47, fig. 21g. 

 Silurian: Europe; Island of Anticosti. 



Orthis daytonensis Foerste. See Hebertella daytonensis. 



Orthis (Dinorthis) deflecta Winchell and Schuchert. See Dinorthis (Plaesiomys) 

 deflecta. 



Orthis deformis Hall. See Schuchertella deformis. 



Orthis(f) delicatula Billings. 



Orthis delicatula Billings, Pal. Fossils, 1, Geol. Surv. Canada, 1865, p. 217. 

 Chazyan (Quebec — N, P): Table Head, Pistolet Bay, and near Portland Creek, 

 Newfoundland. 



Orthis (Platystrophia) dentata Meek. See Platystrophia crassa. 



Orthis desmopleura Meek. See Eoorthis desmopleura. 



Orthis (Plectorthis) desmopleura nympha Walcott. See Eoorthis desmopleura 

 nympha. 



Orthis dichotoma Hall. See Plectorthis dichotoma. 



Orthis disparilis Billings. See Orthis ignicula. 



Orthis disparhis Conrad. See Orthis tricenaria. 



Orthis disparilis Owen. See Dalmanella testudinaria. 



Orthis disparilis Kayser. 



Orthis disparilis Kayser (not Conrad), Paleeontographica, Suppl., 3, 1876, p. 26, 



pi. 3, figs. 4-8. 

 Ordovician: Potrero de los Angulos, etc., Argentina. 



Orthis Electra Billings. See Dalmanella electra. 



Orthis electra var. l^vis Matthew. See Dalmanella electra laevis. 



Orthis electra var. major Matthew. See Dalmanella electra major. 



Orthis elegantula Dalman. See Dalmanella elegantula. 



Orthis elegantula var. parva Foerste. See Dalmanella elegantula parva. 



Orthis ella Hall. See Plectorthis (Encuclodema) sordida. 



Orthis emacerata Meek. See Dalmanella meeki. 



