I go I.] Matthew, Additional Observations on the Creodonta. 23 

 Palaeosinopa didelphoides {Cope). 



Ictops didelphoides CoPE, Bull. Hayden Survey, VI (1881), p. 192 ; Tert. 

 Vert., p. 268. 



Palcdctops didelphoides Matthew, '99, p. 35. 



The lower jaw fragment from the Wind River Beds, referred 

 to Ictops by Prof. Cope, more probably belongs in this genus. 

 In absence of characteristic parts its reference is provisional. 



Sinopa Leidy, 1871. 



Stypolophtis Cope, Pal. Bull. No. 2, Proc. Am. Phil. Soc. 1872, 466. 

 Prototomus CoPE, Report on Fossil Vert. N. M., Ann. Rep. U. S. G. S. W. 

 of looth Mer., 1874. 



Limnocyon Marsh, in part, Am. Journ. Sci. 1872, Vol. IV, p. 122. 



The original types of Sinopa, Stypolophtis, and Litnnocyon were 

 from the Middle Eocene of Wyoming. Cope afterwards described 

 a number of species from the Wasatch under the name of Proto- 

 tomus, which he afterwards (1877) united with Stypolophus. Scott 

 (1892) united both with Sinopa, and an examination of the 

 types of Limnocyon shows that they also should be referred to this 

 genus. 



Besides the characters given on a previous page the following 

 may be noticed : 



Dentition — — -^^-^ . First premolar two-rooted. Brain small. Lower pre- 

 molars composed of principal cusp and trenchant heel (no second posterior 

 cusp). Me. of m- reduced or absent. Incisors small, the upper ones in a row. 



Sinopa rapax Zeidy, 187 1. 



From the Bridger Beds, Wyoming. Type, a lower jaw with 

 more or less broken molars, figured in Extinct Vert. Western 

 Terrs. The species is of medium size with apparently a rather 

 large heel on my, but with vestigial heel {^de Cope, '84, p. 289) 

 on the third. I am unable to find other specific characters in 

 Leidy's figure. Length of P4— nig-, 31mm. 



Sinopa vera {Marsh). 



Limnocyon verus MARSH, Am. Jour. Sci. 1872, Vol. IV, p. 122. 



From the Bridger Beds, Wyoming. A large species with proto- 

 cones of m^- and m^ much compressed. Third premolar nar- 

 row and trenchant. Length of pj-nig-, estimated, 40mm. 



