476 INDEX GENERUM MAMMALIUM. 
Onychogalea—Continued. 
Type: Maeropus unguifer Gould, from the northwest coast of Australia. 
Onychogalea: 6vvé, óvvyoc, claw; y «A5, weasel—in allusion to the horny nail 
or spur at the tip of the tail, whence the common name ‘nail-tailed wallaby.’ 
Onychomys (subgenus of Hesperomys) Barrp, 1857. — Glires, Murid:e, Cricetine. 
Mamm. N. Am., pp. xlii, 457, 458, 1857; BarnLEv, Ann. Rept. U. S. Dept. Agri- 
culture, for 1887, 442-444, 1888 (raised to generic rank); Merriam, N. Am. 
Fauna, No. 2, pp. 1-5, text fig. 1, pl. 1, Oct. 30, 1889. 
Type: Hypud:wus leucogaster Maximilian, from old Fort Clark, North Dakota, on 
the Missouri River, about 100 miles below the mouth of the Little Missouri and 
about 50 miles above Bismarck. 
Onychomys: Ov ve, óvvyos, claw; 40s, mouse—in allusion to the long, fossorial 
claws, which are large in comparison with those of Hesperomys (= Peromyscus. ) 
Onychotherium 6G. FiscuEn, 1814. Edentata, Megalonychid:e. 
Zoognosia, [3d ed., I, 14, 1813—nomen nudum]; III, 132-154, 1814. 
Based on remains from a cavern near Greenbrier, West Virginia. (Equals 
Magalonyx Jefferson, 1797.) 
Extinct. 
Onychotherium: óvv&, Ovvyos, claw; 67píov, wild beast—from the large claws. 
Onychura* Brookes, 1828. Glires, Erethizontid:e. 
** Qat. Anat. & Zool. Museum of Joshua Brookes, London, 54, 1828"' (previous 
to July 14). 
Type: Onychura spinosa Brookes (the ‘spinous Coendou’ ), from tropical America. 
Onychura: 6vvé, óvvyos, claw; obpa, tail. 
Onyx (see Oryx BLAINVILLE, 1816). Ungulata, Artiodactyla, Bovidee. 
Oódectes WonrMAN, 1901. Ferze, Viverridee. 
Am. Journ. Sci., 4th ser., XII, 148-154, figs. 22-30, Aug., 1901. f 
Type: Oódectes herpestoides Wortman, from the Eocene of Wyoming. 
Extinct. Based on the larger part of the skeleton. 
Oüdectes: @Ov, egg; SHKTNs, biter—in allusion to the close relation of Oódectes 
to Iehnewmon, an animal noted for its egg-eating proclivities. 
Ophenodon (see Sphenodon). Edentata, Megalonychide. 
Ophysia (subgenus of Orca) Gray, 1868. Cete, Delphinide. 
Synop. Whales & Dolphins, 8, pl. 1x, 1868; Proc. Zool. Soc. London, 1870, 76; 
Suppl. Cat. Seals & Whales Brit. Mus., 93, 1871 (raised to generic rank). 
Type: Orca capensis Gray, 1846 (=O. pacifica Gray, 1870), from the North Pacific. 
Opisthotomus Corr, 1875. Primates, Notharctidze. 
Syst. Cat. Vert. Eocene New Mexico, 13, 15-16, Apr. 17, 1875; Hav, Cat. Foss. 
Vert. N. Am., Bull. 179, U. S. Geol. Surv., 792, 1902 (type fixed). 
Species: Opisthotomus astutus Cope (type), and O. flagrans Cope, from the Eocene 
of New Mexico. 
Extinct. 
Opisthotomus: Om16bev, behind; rods, cutting—in allusion to the posterior lower 
molar which has a series of three cusps in one line ‘‘and would appear by its 
form to be capable of a sectorialfunction." (Cope. ) 
Opistorinus Brayarp, 1857. Ungulata, Litopterna, Macraucheniide. 
‘“Observations Géol. Bassin de La Plata, 1857"' (fide Gervais, Zool. et Paléont. 
Gén., I, 132, 1867). 
Opisthorhinus BRAvARD, in Burmeister's Desc. Macrauchenia patachonica, Anal. 
Mus. Pub. Buenos Aires, entr. 1, 33-34, pls. 1-111, 1864. 

* This name is open to question, as it is published in a sale catalogue. 
