96 



osborn: OLIGOCENE, MIOCENE, PLIOCENE EQUID.E. 



by a right astragalus, a second phalanx, a proximal part of a metacarpal, and a fragment of a tooth. The tooth from 

 the upper jaw, Florida Survey collection No. 5084, is selected as the type of the species." Measurements: (Sellards, 

 p. 83). 



"Anteroposterior diameter of tooth, probably m 1 16 mm. 



Transverse diameter, at base 19 mm. 



Transverse diameter from summit median ridge to inner margin 15 mm. 



Height of crown, tooth but slightly worn 13.5 mm." 



Type figure. — Text Fig. 72 of this Memoir. 



Characters. — (Sellards, pp. 83-85) "The tooth selected as the type is but little worn and serves well to show the 

 characters of the species. . . .Of the described species of Parahippus this species presents apparently a rather close resem- 

 blance to Parahippus (Anchippus) texanus (Leidy). 1 From that species, however, it differs first of all in size, the antero- 

 posterior diameter of the tooth being l(i mm. while that of the Texas species according to Gidley is 19 mm." 



(?) PROCAMELUS-HIPPARION ZONE. 



The following species is attributed to the Madison Valley formation of Montana (Douglass, 1899). 



Parahippus minimus Douglass 1899. 

 Text Fig. 72a. 



A[n]chitherium minimus, n. sp., Douglass, Earl. "The Neocene Lake Beds of Western Montana and Descriptions of Some New 

 Vertebrates from the Loup Fork," Thesis for Degree of M.S., published by the University of Montana, June, 1899, pp. 26-27, no figure. 



Horizon and locality. — (Douglass) "Both the above specimens were found in the Loup Fork formation in the lower 

 Madison valley, western Montana." Collected by Earl Douglass, 1895. Douglass (letter Oct. 20, 1917) confirms the 

 finding of this type in the Madison Valley formation (Lower Pliocene). 



Type and paratype. Carnegie Mus. Nos. 713, 713a, 714. (Douglass, 1899, p. 26) " . . .two specimens consisting of 

 the five upper posterior cheek teeth [type, Carnegie Mus. 713, paratype, 713a] and a mandibular ramus [paratype, Carnegie 

 Mus. 714] of another individual. The jaw fragment contains the symphysis and the incisors, some of which are broken. 

 I refer both of these fragments to the same species, as they correspond in size, and there is no reason to believe that they 

 belong to separate species." Measurements: length of upper posterior five cheek teeth .067, length of upper molar series 

 .0415, length of mandible to m : j .111. Full measurements are given by Douglass, op. cit. pp. 26, 27. 



(Osborn, 1918) The type superior molars were regarded by Douglass as a successive series of five teeth, p 3 -m 3 , 

 belonging to one individual. They are regarded by Matthew (1917) as belonging to two individuals, namely, three 

 teeth, p'-m 1 , constituting the type (Carnegie Mus. 713), and two teeth, a molar and a premolar (one of which has been 

 misplaced), belonging to a larger animal (Carnegie Mus. 713a). 



Type figure. — Text Fig. 72a of this Memoir. 



Characters. — (Douglass, 1899, pp. 26, 27) Type. (1) I use Anchitheri inn in the restricted sense in which Scott has 

 used it, the Madison species thus being, so far as I know r , the second found in America. (2) It is much smaller than A. 

 aurelianense Cuv. or J. equinum Scott. It differs from A. equinum in the following respects: (3) in p 3 cross crests united 

 by an isthmus across the median valley, thus forming two enamel lakes, as in modern horses; in p 4 protoloph does not reach 

 outer wall of crown; (5) posterior pillar proportionately larger than in Scott's specimen; (6) a small pillar at the entrance 



1 "Extinct Mammalian Fauna of Dakota and Nebraska," Jour. Acad. Nat. Sci. Phila. (2) Vol. VII, 1869, pp. 312-313, pi. XXI, 

 fig. 13. 



