1898.] Osborn^ Evoluthn of the Ainblypoda. Part I. 



209 



10. C. molestjts Cope. Type, U. S. Nat. Mus. Coll. Skull, dentition and 

 parts of skeleton. Loc, New Mexico. 



11. C. lomas Cope. Type, U. S. Nat. Mus. Coll. Posterior inferior molar. 

 Loc, New Mexico. 



_ 'yphoiioH a)')iiaiits siipe- 



riiir molars, left side (type of C. molest us 

 Cope). 



The slender crests and the elongate form of the posterior lower 

 molars in this species at once distinguish it as a type from mem- 

 bers of the foregoing series, since they form an angle of 81'', or 

 nearly a right angle, with the long axis of the jaw, and m3 is 

 entirely devoid of the entoconid (Fig. 16). 



Specimen No. 4315, Fig. 17, gives 

 the most distinctive character, 

 shown again in Cope's type of C. 

 jiiolesti/s (Cope, 1877, PI. LVI, fig. 

 4), which agrees with C. an/iatus, 

 namely, the flattened form of the 

 canines. Cope himself referred C. 

 I 01)1 as to C moles tus (1877, p. 237). 

 The type of C. simi/s has lower 

 teeth of the same character, rather 

 long and narrow. The upper 



canines are, however, described by Cope as triangular and 

 grooved ; this raises a doubt as to the reference of this type to C. 

 armatiis. 



The juvenile type specimen of C. luolcstiis demonstrates the 

 flat-topped character of the skull (Coll. U. S. Nat. Mus. No. it 19, 

 Cope, op. cit., PI. LVI) ; the skull is far less expanded laterally, 

 when seen from above, than any of the skulls in Series II ; 

 but this may l)e in part due to its juvenile and undeveloped 

 condition. 



" The inferior canine," observes Cope, " has a flat interior and 

 convex exterior face, which are separated by anteriorly and pos- 

 teriorly directed cutting edges." The most distinctive feature 

 of the canines therefore is that the antero-posterior diameter 

 greatly exceeds the transverse, as in Uintatheriuin. An aberrant 

 feature is the antero-external groove. The median incisors are as 

 large or larger than the others. 



^May, iSgS.\ II}. 



