iQoi.] Gidley, The North American Species of Equus. 



109 



(6) Equus complicatus {Leidy 



E, americanus Leidy (non Gervais). 



Type Locality. — Near Natchez, Missis- 

 sippi. 



Horizon. — Tenaceous blue clay under- 

 lying a diluvial deposit. 



Type, — A second superior molar of the 

 left side. Cotypes : Two third superior 

 molars of the right side. 



Author s description. — " The enamel 

 folds are one-fourth thicker than in the 

 recent horse and the isolated enamel folds 

 of the superior molars are much more 

 plicated, resembling in this respect the 

 Equus plicidens, Owen." 



Measureme7its. 

 { Antero-posterior diameter =1.2 



30 mm. 



2 J of an inch = 



I Transverse diameter = i.i of 



[ an inch = 27 mm. 



When Leidy first described this 

 species he gave it the name E. 

 americanus, but, as explained above 

 (4), he later substituted the name 

 E. complicatus.^ This name was 

 employed by Leidy for some time,'' 

 but in his great Memoir of 1869 

 (Leidy, 1S69, p. 264) he made E. 

 complicatus a synonym of E. major., 

 apparently without any justifiable 

 reason, stating only that he sus- 

 pected these two species to be the 

 same. Thus, although^, major \\z?> 

 employed continuously by Leidy 

 and by Cope until 1899,' the name 

 really has no standing and E. com- 

 plicatus should be retained. 



The species E. complicatus itself 

 is imperfectly characterized'except 



Fig. 7. Type of Equus complicatus^ 

 A, triturating surface ; A'^, side view of 

 crown. (After Leidy.) 



'■ Proc. Acad. Nat. Sci. Phila., 1S58, p. 11. 

 - Holmes's Post-Pleioceiie of So. Carolina, i860. 



^ On p. 259 of the Port Kennedy Cave .Memoir (Cope, gg). Cope remarlced that having looked 

 nto De Kay's account he finds no definite application of the term, £. major, can be made. 



