ISODON—ISOTEMNUS. 9090 
Isodon Say, 1822. Glires, Octodontide. 
Journ. Acad. Nat. Sci. Phila., II, pt. 2, p. 333, Nov., 1822; WaATERHOUSE, Nat. Hist. 
Mamm., II, 286, 1848 (date of publication, under Capromys). 
Type: Jsodon pilorides, from Cuba. 
Name preoccupied by Jsoodon Geoffroy, 1817, a genus of Marsupialia. 
Tsodon: i60$, equal; 666v=dsovs, tooth—in allusion to the molars, which 
have flat crowns, “‘ traversed equally from the base to the summit by laminze, 
which on the summit and base of the tooth terminate precisely alike, in zigzag 
lines" ~(SAy.)) ; 
Isolophodon Rorn, 1903. Ungulata, Astrapotheroidea, Astrapotheriide. 
Revista Mus. La Plata, XI, 142, 1903. 
Species: Jsolophodon cingulatus Roth, from the lower Tertiary of Canadon Blanco; 
and I. aplanatus Roth, from the ‘upper Cretaceous’ of Lago Musters—both 
from the Territory of C :ubut, Patagonia. 
Extinct. 
Tsolophodon: 260€, equal; Ad@os, crest; 65@v=650vs, tooth. 
Isomys SuNDEVALL, 1842. Glires, Murid:e, Murine. 
K. Svenska Vetensk. Akad. Handl., Stockholm, 219-220, 1842. 
Type: Mus variegatus Lichtenstein (— Lemmus niloticus Geoffroy), from north- 
ern (?) Egypt. 
Tsomys: 160s, equal; 4s, mouse. 
Isoodon (‘Grorrroy’) DesmMArest, 1817. Marsupialia, Peramelid:ze 
Desmarest, Nouv. Dict. Hist. Nat., 2d ed., XVI, 409-410, 1817;* XVIII, 511 
footnote, 1817. 
Type: Didelphis obesula Shaw, from Australia. 
Tsoodon: i60s, equal; 000v —0800«, tooth. 
Isoptychus (subgenus of Theridomys) PowEL, 1854. Glires, Theridomyid:ze. 
Cat. Méthod. Vert. Foss. Bassin de la Loire, 34-36, 1854; Grrvars, Zool. et Paléont. 
Francaises, 2° éd., 33-34, 1859 (synonym of Theridomys). 
Tpsotychus TRovEssanT, Cat. Mamm. Viv. et Foss., Rodentia, in Bull. Soc. d? Études 
Sci. d'Angers, X, 2* fasc., 166-167, 1881 (misprint). 
Species, 6: from the Tertiary of France: /soptychus jourdani Pomel, from Puy; I. 
vassoni Pomel, from Sauvetat; Theridomys aquatilis Aymard, from Puy; Isop- 
tychus cuvieri Pomel; I. aubery Pomel, from Péréal, Vaucluse; and ZI. antiquus 
Pomel from Péréal, Vaucluse. 
Extinct. 
Tsoptychus: 1605, equal; zr08, zrvyóc, fold, plate—in allusion to the three enamel 
grooves of the upper molars which differ little in length. 
Isostylops AMEGHINO, 1902. Tillodonta, Notostylopide. 
Bol. Acad. Nac. Cien. Córdoba, XVII, 33, May, 1902 (sep. p. 31). 
Type: Isostylops fretus Ameghino, from the Notostylops beds of Patagonia. 
Extinct. 
Tsostylops: t605, equal, even; 6rÜAos, pillar; Ow, aspect. 
Isotemnus AwxaniNo, 1897. Ungulata, Ancylopoda, Isotemnidee. 
La Argentina al través de las Ultimas Epocas Geoldgicas, 16 footnote, 25, 1 fig. 
in text, 1897; Bol. Inst. Geog. Argentino, XVIII, 480-482, fig. 62, Oct. 6, 
1897. 
Species: Jsotemnus primitivus Ameghino, and 7. conspiquus Ameghino, from the 
‘Cretaceous’ of Patagonia. 
Extinct. 
Tsotemnus: 760s, equal; r£uvc, to cut. 


* ** Établi en juillet 1817, par M. Geoffroy Saint-Hilaire, dans son cours publie de 
zoologie, au Muséum d'Histoire naturelle de Paris."  (DEswaREsr.) 
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