igo2._ 



Osborn, American Eocene Pn'tnates. 



209 



No. 4195), with molar teeth (ms. = ii.5 mm.) in nearly parallel series; 

 anterior pair apparently well developed and procumbent; lower pre- 

 molars spaced, pa with paired fangs; P4 a sub-quadritubercular tooth, 

 namely with protoconid, tritoconid, deuteroconid, and tetartoconid ; 

 molars with narrow trigonid, paraconid small but distinct and median 

 in position, broad talonid with a small hypoconulid. The ramus is 

 long and rather slender, and the angle is produced posteriorly. 



Cynodontomys is barely distinguished from its successors in 

 the Wind River and Bridger by the less complete transforma- 

 tion of the fourth 

 premolar and by 

 the smaller single 

 incisor. It is repre- 

 sented also by the 

 juvenile jaw (No. 

 65), by the speci- 

 men (No. 4184) re- 

 ferred to Chriacus 

 angulaUis by Cope. 



Cope erroneously 

 referred to this species a number of specimens from the 

 Wasatch and Wind River horizons, with a short deep 

 mandibular ramus, small heels upon the third lower molars, 

 and general structure more similar to the Bridger series 

 described below; ms. = 13.5 mm. 



3. Wind River (Lutetien) Stage. 

 Genus MICROSYOPS Leidy. 

 PalcBacodon Leidy, Bathrodon Marsh, Mesacodon Marsh. 



(Sp. 46) Microsyops scottianus Cope. — Type: A long, shallow 

 mandible (Amer. Mus. No. 4748), large semi-procumbent tooth with 

 narrow diastema behind it; ms. = i4 mm.; formula: y, j, 5, 5. 



Fig. 35. Cynodontojjiys latidens. Type. Cope Coll- 

 No. 4195 Wasatch. Big Horn Valley, Wyoming. Twice 

 natural size. 



Fig. 36. Microsyops scottianus. Am. Mus. No. 4748. Slightly less than 2 diam. 



u 



