ORTHOMYS—ORYCTEROPUS. 483 
Orthomys—Continued. 
Extinct. Based on incisors. 
Orthomys: ópfióc, straight; 0s, mouse. 
Orthotherium (see Ortotherium). * Edentata, Megalonychid:e, 
Orthriomys (subgenus of Wicrotus) Merrtam, 1898. — Glires, Muridze, Microtinee. 
Proc. Biol. Soe. Wash., XII, 106-107, Apr. 30, 1898. 
Type: Microtus umbrosus Merriam, from Mt. Zempoaltepec, Oaxaca, Mexico. 
Orthriomys: Op§ptos, early; 0s, mouse. The genus ‘‘suggests an ancient type 
intermediate between Phenacomys and the microtine subgenera Pedomys and 
Arvicola." (M&rR1IAM. ) 
Orthutaetus AmEGHINO, 1902. Edentata, Dasypodide. 
Bol. Acad. Nac. Cien. Córdoba, XVII, 63, May, 1902 (sep. p. 61). 
Species: Orthutaetus crenulatus Ameghino, and QO. clavatus Ameghino, from the 
Notostylops beds of Patagonia. 
Extinct. 
Orthutaetus: dp90s, straight; + Utaetus. 
Ortomyctera (see Orthomyctera). Glires, Caviidee. 
Ortotherium AMEGHINO, 1885. Edentata, Megalonychid:e. 
Bol. Acad. Nac. Cien. Córdoba, VIII, entr. 1, pp. 111-115, 1885; Cont. Conoci- 
miento Mamíf. Fósil. Repüb. Argentina, in Act. Acad. Nac. Cien., Córdoba, 
VI, 684-685, pls. Lxx fig. 2, Lxxr figs. 12-13, 1889. 
Orthotherium RoaER, Bericht Naturwiss. Ver. Schwaben u. Neuburg (a. V.), 
XXIX, 17, 1887; Zirret, Handb. Palaeont., IV, 134, 1892; TrovuEssart, Cat. 
Mamm., new ed., fasc. V, 1100, 1898. 
Type: Ortotherium laticurvatum Ameghino, from the barrancas del Paraná, 
Argentina. 
Extinct. Based on the left mandible. 
Ortotherium: Ójfós, straight; Gypiov, wild beast—in allusion to the rectangular 
alveoli of the lower molars. 
Qrycterocetus Lripy, 1853. Cete, Physeteride. 
Proc. Acad. Nat. Sci. Phila., for 1852-53, 378, 1853; ibid., 1856, 255; Journ. Acad. 
Nat. Sci. Phila., 2d ser., VII, 436, 1869. 
Type: Orycterocetus quadratidens Leidy, from the Miocene of Virginia. 
Extinct. Based on ‘fragments of both sides of a lower jaw, two teeth, anda 
portion of a rib.’ 
Orycterocetus: 6pvKTNpP, digger; x?jroc, whale. 
Orycteromys* Picrer, 1842. Glires, Murid:ze, Cricetinze? 
* Verhandl. Schweiz. Naturf. Gesellsch. zu Altdorf, 1842, 192" (fide WAGNER, 
Wiegmann's Archiv Naturgesch., 1844, Bd. 2, p. 172). 
Type (species not mentioned by Wagner), from Bahia, Brazil. *'Die Gattung 
Orycteromys, die von den Ratten nur durch einige Details im Zahnbau und 
starke Nigel an den Vorderfüssen abweicht.”’ 
Orycteromys: OpvKTNpP, digger; 40s, mouse. 
Orycteropus Grorrroy, 1795. Effodientia, Orycteropodid:e. 
** Décade Philosophique, 1795" (fide AGasstz, Nomencl. Zool., Mamm., 25, 1842); 
Bull. Sci. Soc. Philomatique, Paris, I, for 1791-96, 102-103,+ Apr.—June, 1796; 

99 
*This name is erroneously referred by Agassiz (Nomenclator Zool., Mamm., 23, 
1842), to De Blainville, Bull. Soc. Philomatique, 1826. The name proposed by De 
Blainville in this volume, p. 64, is however Ctenomys and not Orycteromys. 
+ ** Établi en 1791, par Et. Geoffroy Saint-Hilaire ( Mag. Encycl., t. VI; et Bull. de 
la Soc. Phil. de Paris, t. I)." (D'Orbigny's Dict. Hist. Nat., IX, 228, 1849.) The 
date, however, does not agree with that for the mammal part of the Encycl. Méth. as 
given by Sherborn in P. Z. S. 1893, 582-584, and it is doubtful if there is any earlier 
description than those cited above. 
