3 



The clog which I referred to the genus Enhydrocyon (Cope) under the 

 name of E. basilatits, probably belongs to another genus. Portions of the 

 maxillary bone present the dentition of Icticyon, viz., P-m. 4, M. 1, thus 

 differing from Enhydrocyon, which possesses P-m. 3; M. 2. As there are 

 but three premolars in the inferior series, this species cani >t be referred to 

 Icticyon, but must be accepted as typical of a new genus. This I propose 

 to call Hymnocyon. It resembles Rymna more nearly than any genus yet 

 discovered in North America, but probably belongs to the Ganidm. 

 Amphicyon entoptychi, sp. nov. 



This rather small species is represented by a skull which lacks the ex- 

 tremity of the muzzle and the mandible, and has its parietal region crushed. 



The superior premolar teeth are rather short in anteroposterior diameter, 

 while the tubercular molars are relatively large. There are no posterior 

 lobes on the former ; the internal and external cingula are well developed 

 in the first and second of the latter. The third tubercular is about as wide 

 as the second is long. The sagittal crest is only distinct on the posterior 

 part of the parietal region. Estimated length of skull, M. .110; length 

 of superior molar series, .011 ; length of true molar series, .016 ; length of 

 first tubercular, .0075; length of second tubercular, .055; width of second 

 tubercular, .0074; length of third tubercular, .0036; width of third tuber- 

 cular, .052 : L*ehgth of sectorial width between anterior external angles of 

 first tuberculars, .030. 



The teeth of this species are about half the size of those of A- ve'.tts Leidy. 

 Arcit.elurus debilis Cope. 



American Naturalist, 1879, p. 798a, Dacember. 



Char. gen. Dentition, I. f ; C \ ; P-m. f ; M. \ ; mandible with the 

 anterior face of the symphysis separated from the lateral face by an angle 

 which is not produced downwards. Superior sectorial without anterior 

 lobe ; inferior sectorial with heel. The characters place ArcJuelurus at the 

 base of the Fdidce. showing that it is the most generalized form yet known, 

 and about equally related to the feline and Machoerodont series. 



Char, specif. General structure of the jaws weak. Superior canine 

 small, little compressed, with an acute posterior edge which is not serru- 

 late. First premolar in each jaw one-rooted ; second inferior premolar 

 large ; sectorials large, diastemata very short. Alveolar border below the 

 inferior sectorial and tubercular teeth everted, forming a large osseous 

 callus, which has a free inferior and posterior margin, the latter rising into 

 the base of the coronoid process. Zygomata slender ; postorbital processes 

 little prominent ; front wide, convex transversely. 



Length of cranium, M. .200 ; superciliary width, .052 ; zygomatic width, 

 .124 ; length from orbit to superior incisors, .066 ; length of superior secto- 

 rial, .023 ; length of inferior molar series, .064; diameter of superior canine, 

 <012. About the size of the panther, or of the JSfimravus brachyops. 



The osseous callus below the true molars is a remarkable character, 

 unique in the order of Gurnivora. It is evidently a provision against the 

 weakness of the mandibular rami, at the point of greatest strain. 



