416 F. B. Loomis — Hyopsodidce. 



Art. XLI V. — Hyopsodidce of the Wasatch and Wind River 

 Basins ; by F. B. Loomis. 



During the early summer of 1904, Amherst College sent a 

 party into the Wasatch along the Big Horn Biver, where an 

 unusually complete collection was obtained : later, collecting 

 was continued in the Wind Biver beds, a new and rich locality 

 having been found on the east side of Bridger Creek, about 

 ten miles northwest of Lost Cabin Post Office, Wyoming. In 

 the latter basin, the fauna of which has been but meagerly 

 known, some 400 specimens, distributed among about 50 

 species, were found. As a large number of the species are 

 new,, the material, together with that of the Wasatch, has been 

 used in a study of the families represented ; reference also 

 having been made to other collections from these horizons, 

 especially those of Cope and the American Museum of Natural 

 History, both being in that museum. 



Order Insectivora. 

 Family Hyopsodidm, Schlosser. 



This family as now known includes two genera, Hyopsodus 

 and Sarcolemur, both from the North American Eocene. The 

 genera were originally classed among the Primates ; and so in 

 Cope's* and Osborn'sf papers are placed under the suborder 

 Mesodonta; or by SchlosserJ under the equivalent Pseudo- 

 lemuroidea. Wortman,§ however, has classed them among the 

 Insectivora, giving the following reasons : 1, the incisors are 

 3/3 ; 2, the tympanic bulla is not ossified ; 3, the structure of 

 the molars is not Primate ; 4, the enterocarotid circulation is 

 that typical of the Insectivora : 5, the limb bones differ from 

 those of any known Primate ; 6, the metapodials are not Pri- 

 mate ; 7, the phalanges are short ; 8, the hallux is not opposa- 

 ble. The writer too would place the Hyopsodidse among the 

 Insectivora and in the neighborhood of the genus Frinaceus. 



The family may be defined as follows : teeth in a continuous 

 series, cusps more or less pointed ; superior molars with inter- 

 mediate cusps (protoconule and metaconule) ; posterior internal 

 cusp (hypocone) less developed than the other cusps ; the 

 lower molars with a low anterior buttress (protolophid) con- 

 necting the two anterior cusps ; a second buttress behind the 

 first, connecting the same cusps posteriorly (metalophid) more 

 or less developed ; the entoconid feebly developed (see fig. 1). 



*Kep. U. S. Geol. Surv., iii, 738, 1884. 



f Bull. Amer. Museum Nat. Hist., 178, 1902. 



% Die Affen, Lemuren, Chiropteren N. S. W., 21, 1890. 



§ This Journal, xv, 400, 1903. 



