Scott.] 



244 



[May 18, 



teeth, the examination of which has yielded some very surprising 

 results. Not only is the conjecture confirmed that Artumyx and Agrio- 

 cJioervs are synonymous names, but also that the forelimb which I de- 

 scribed as ? Mesonyx dakotenns (Proc. Acnd. Nat. Sci., Phila., 1892, p. 

 306) probably belongs to some nearly allied form. Agrioclicerus has thus 

 almost as many synonyms as ChaUcotherium, and as in that animal its 

 various parts liave been referred to no less than three mammalian orders, 

 the head to the artiodactyls, the fore foot to the creodonts and the hind 

 foot to the Ancylopoda. 



Thefe preliminaiy notes will deal onl}' with some of 

 the more salient features of structure, leaving a com- 

 plete account of tlie skeleton for another occasion. 

 Beside the three parts of skeletons already mentioned, 

 the material at present available consists of the fore 

 leg and part of raanus, lacking ungual phalanges, of 

 the specimen described as ? Mesonyx dakotenfin (Mu- 

 seum No. 10493), and a second very similar specimen 

 collected last summer by Mr. Hatcher (No. 10695). 



The skull of AgriocJicerus departs very little from 

 that of the oreodonts, even those features in which it 

 differs from the White River members of that familj', 

 such as the open orbit and (probably) the absence of 

 the lachrymal pit, being shared by Protoreodon of the 

 Uinta Eocene. 



The dentition displays the preeminently character- 

 istic feature of the oreodonts in the conversion of the 

 inferior canine into a functional incisor, while p. 1 

 assumes the form and function of the canine In other 

 respects the dentition is widelj^ different from that of 

 the oreodonts. Briefly stated, these differences are as 

 follows : (1) The reduction of the upper incisors ; 

 (2) the molariform pattern, more or less complete, of 

 p. 4 in both jaws ; (3) the structure of the molars, 

 which closely resemble those of ffyopoiamvs, though 

 lacking the protoconule in the upper series. These 

 differences induced Leidy to refer Agriocli(&rvs to a 

 family distinct from, but allied to the oreodonts. 



The proximal end of the radius is almost exactly 

 like that of Oreodon ; it is transversely extended, oc- 

 cupying the whole widih of the humeral trochlea and 

 viajorf % nat. size, antero-posteriorly compressed. The proportions of the 

 The ulna is too much ^Yiree humeral facets are slightly different from those 

 shortened in the « ^ , , , . , . , 



drawing °^ Oreodon, the outer one being relatively narrower 



and the pit for the intercondylar ridge of the humerus 

 larger and deeper. This applies, however, only to the large species 

 from the upper beds ; in A. antiquns the correspondence of this por- 



Fjgl 



Fig. 1. Left ulna 

 and radius of A. 



