SUBORDER B 



DILAMBDODONTA 



43 



Family 6. Adapisoricidae Lemoine. 



Small extinct and little-known Insedivora with 2 /, 1 C, 4 P, 3 Tlf in the lower 

 jaw. Upper M are trituhercular. Lower I small and rodent-like. C small. 

 P two-rooted toith principal {primary) cusp and talonid. M with high, three- 

 pronged trigonid and strong grooved talonid. Systematic position absolutely uncertain. 



Adapisorex and Adapisoricidiis Lemoine in the Lowest Eocene of Cernay 

 and Ay near Rheims. 



3.L4.3. 



Family 7. Hyopsodontidae Schlosser. 

 Skidl low, snout fairly long, with broad brow and occiput. Upper M 



square, with six tubercles, lower quadritubercular, trigonid scarcely higher than 

 talonid. All front teeth with single cusp, almost forming a closed series, with gradual 

 transitions from one to the next. Upper P^ to P'^ with inner cusps, lower P^ very 

 complicated. 



This extinct family was, until very recently, placed among the Primates on 

 account of the similarity of the dentition. The skull, however, shows many 

 similarities to that of Erinaceus, and the metapodials also do not have button- 

 shaped, but keeled articular facets. Also the pollex and hallux are not 

 opposable. Connected with the small Mioclaenidae. 



rta. 



Hyopsoclus paulus Leidy. M. Eocene ; 



Biidger beds of Wyoming. A, Inferior 



aspect of upper molars, ^/i. B, Superior 

 aspect of lower molars, 2/j. 



j^.nvf 



P3P- P'^P- 



Hyopsodus decipiens Matthew. Bridger beds of Middle Eocene ; 

 Wyoming. Skull and mandible, i/j. (After Matthew.) 



Hyopsodus Ijeidy (Lemuravus Marsh) (Figs. 69, 70). /, 6' and the front P 

 are pointed and cone-shaped, P^ and P^ with large, thick-set outer cusps and 

 V-shaped inner cusps. Upper M with two angular outer tubercles, two 

 V-shaped inner tubercles, and two well-developed median tubercles. Lower 

 P^ with large median cusp and two-ridged talonid. Lower 31 with four 

 blunt indistinctly alternating tubercles and a small hind tubercle. The orbit 

 is on the side of the broad skull ; the tympanic does not form an ossified 

 bulla. Humerus with entepicondylar and supratrochlear foramina. Limb- 

 bones like those of Erinaceus. Astragalus with flat trochlea. Terminal 

 phalanges small, rounded, and not divided. Numerous species in the Eocene 

 of North America. From Wasatch beds, H. lemoiniamts, miticulus Cope. 



