ENTOCASMUS—EOAUCHENIA. 261 
-Entocasmus AmeEcuino, 1891. Edentata, Ganodonta, Stylinodontid:e. 
Revista Argentina Hist. Nat., I, entr. 3a, 139, fig. 57, June 1, 1891. 
Type: Entocasmus heterogenidens Ameghino, from the Lower Eocene of southern 
Patagonia. 
Extinct. 
Entocasmus: àvróc, within; y&6j«a, hollow, gulf—in allusion to the enamel of 
the teeth, ‘‘siempre cubierto por una capa de cemento muy espesa.”’ 
Entomacodon MansH, 1872. Insectivora, Leptictidz. 
Am. Journ. Sci. & Arts, 3d ser., IV, 214-215, Sept., 1872 (sep. issued Aug. 13). 
Type: Entomacodon minutus Marsh, from the Eocene of Henry Fork of Green 
River, Wyoming. 
Extinct. Based on ‘‘a fragment of a lower jaw with the last molar perfect." 
Entomacodon: &vroyov, insect (i.e. insectivore?); di», point; óó0cv-—Ó000vs, 
tooth. s 
Entomodon Marsu, 1872. Primates, Hyopsodidee? 
Am. Journ. Sci. & Arts, 3d ser., IV, 214, Sept., 1872 (sep. issued Aug. 13); OsBorn, 
Bull. Am. Mus. Nat. Hist., N. Y., XVI, 173, 180, 189, June 28, 1902 (under 
Sarcolemur ). 
Type: Entomodon comptus Marsh, from the Eocene of Henry Fork of Green River, 
Wyoming. 
Extinct. Based on ‘‘several isolated teeth, one of the most characteristic of 
which is a last lower molar, in excellent preservation." 
Entomodon: &vrouov, insect; 66@v—=d6 ov, tooth. 
Entoptychus Corr, 1878. Glires, Heteromyidee? 
Palzeont. Bull, No. 30, pp. 2-4, Dec. 3, 1878; Proc. Am. Philos. Soc., XVIII, 
64-66, Dec. 30, 1878; Hav, Cat. Foss. Vert. N. Am., Bull. 179, U. S. Geol. 
Sury., 731, 1902 (type fixed). 
Endoptychus: Dauron, Geol. Record for 1878, 293, 432, 1882 (misprint). 
Species, 3: Hntoptychus cavifrons Cope (type), E. planifrons Cope, and EF. crassiramis 
Cope, from the Miocene (John Day) of Oregon. 
Extinct. 
Entoptychus: évr6s, within; zr08&, zrvyós, fold—from the molars, which when 
young have a deep inflection of enamel from one side. 
Enydris (see Enhydra). Fere, Mustelid:e. 
Eoauchenia* Amecuino, 1887. Ungulata, Artiodactyla, Camelide. 
Apuntes Prelim. sobre Mam/ff. Estinguidos de Monte Hermoso, 16-17, Apr., 1887; 
Cont. Conocimiento Mamíf. Fós. Repüb. Argentina, in Act. Acad. Nac. Cien., 
Córdoba, VI, 598-599, 1889. 
Type: Hoauchenia primitiva Ameghino, from Monte Hermoso, about 40 miles east 
of Bahia Blanca, province of Buenos Aires, Argentina. 
Extinct. Based on various separate bones. 
Eoauchenia: 20s, dawn; + Auchenia—i. e., a primitive Auchenia. 


*The prefix eo- was proposed by Owen to indicate a genus occurring in the Eocene 
and his suggestion has been generally adopted by later authors. The term Eocene 
was invented by Lyell, as Owen explains (Brit. Foss. Mamm., 5, 1846), to indicate 
“the first commencement, or dawn, of the existing state of the animal creation." 
Dobson afterwards used eo- in the sense of ‘eastern’ for a recent genus, and the prefix 
has been employed with this meaning for a few groups of mammals from the Ori- 
ental and Ethiopian regions viz, Honycteris, Eosciurus, Eothenomiys, Eoverus, and 
Eozapus. 
