igor.] Gidlcy, The North Ajuerican Species of Eqinis. 12J 



internal wall of the paracone and metacone, from which it results that the ex- 

 terior border of each of the lakes is deeply concave, and the horns appear to be 

 strongly produced. The protocone has a very short antero-posterior diameter, 

 in which it resembles the E. simplicideiis^ E. crenidens, and E. stenonis, and 

 differs radically from the E. tau and the other species of the Equus beds. It is 

 not bilobate or grooved on the internal face. . . . The subcylindric char- 

 acter of the paracone and metacone approach what exists in ' Hippidium ' and 

 some species of the three- toed horses." 



Aleasnreinents given. 

 The measurements of the best-preserved crown are: length, 33 mm.; trans- 

 verse diameter, 24 mm.; antero-posterior, 24 mm. 



This species was founded on three superior molars, two of 

 which were figured by Cope. (See Figure 17.) Both the de- 

 scription and the figures show some char- ^ 

 acters that seem to mark its close relation P. '"^-"■•--t^^,^^^p==\ 

 with the three-toed horses, and like those ':;,. / jiW^^Um 

 given by Cope for the distinction of his E. Hv/^J\ jf 

 eiiry stylus and E. si/npliddens they show no 'ji ^^^'^st^/^"'^ 

 characters that indicate any connection ^^^ ^=^^^'/ 

 with the genus Eqmis. The very small ^^^^^^^^^^ 

 size and form of the protocone seems es- Fig. 17. Type of Proto- 



.,, ^ -J ^- r ^,- • -.1.1 hippns cumiiiitisii (Egmts 



peCially to identify this species with the aninnhisH Co-ps). Superior 

 T -r^ 1 1 •, , • molar. (After Cope.) 



Loup Pork genera, and its extreme sim- 

 plicity of enamel folding of the tooth crown seems to place it in 

 the genns Erotoh/ppns. 



(19) Protohippus phlegon {Hay). 



Eqiiits phlt'gon Hay. 

 Synonym, Eqints niinutus Cope. 



Type Locality. — Mount Blanco, Texas. 



Horizon. — Blanco Beds. 



Type. — An inferior molar — (?) m^. 



Author s description. — " The inferior molar is narrowly hypsodont, and has 

 apparently had but a thin cementum investment. . . . The inner side of 

 the crown shows marked peculiarities. The metaconid and metastylid are ap- 

 pressed to the hypoconid and protoconid, and are spread widely apart so as to 

 be connected by a narrow antero-posterior isthmus, and separated on the internal 

 face of the crown by a wide channel which has a greater antero-posterior diameter 

 than the metaconid and metastylid respectively, near the apex of the crown, 

 and an equal width at the base of the crown. The hypostylid (entoconid) is also 

 appressed to the hypoconid and has a recurved postero-internal angle, which 



