184 PROCEEDINGS OF THE ACADEMY OF [1879. 



From the Truckee beds of the White River formation in Oregon. 



Canis, Linn. 



The names proposed by Smith, Gray, and others, and which 

 must be regarded as synon3 T ms of Canis, are Lupus, Dieba, Si- 

 menia, Chrysocyon, and Lycalopex. Man}' of the species, referred 

 to by European paleontologists under the name of Cynodictis, 

 Pomel, appear to me to be undistinguishable from Canis. Through 

 the great kindness of M. Filhol, I possess specimens of the jaws 

 of several of these species. A mandible with nearly complete 

 dentition of the Cynodon velaunum of Aymard, agrees very 

 nearly with the jaws of some of the smaller species from the Ame- 

 rican White River beds, which I have referred to Canis. Helocyon, 

 Aym. may be distinct, but may not belong to the Ganidce. 



The dentition of man}' of the recent species of Canis differs in 

 very slight characters. The following may be detected in an ex- 

 amination of the superior molars of the three larger species most 

 accessible in the United States. 



Last superior tubercular short, wide; inner cingulum and crest 

 nearly confounded. 



Inner crest of tub. m. I. composed of two low tubercles. 



C.familiaris. 

 Vars. molossus, terrarius, graius. 



Last superior tubercular narrower, transverse ; inner cingulum 

 very distinct. 



Inner crest of tub. M. I., a ridge higher anteriorty. C. lupus. 

 Inner crest of tub. M. I. with two sharp cusps. C. latrans. 



It is worthy of note that the wide oval form of the second supe- 

 rior molar of the Canis familiaris, exists equally in the extreme 

 races or species, the gra3diound and bulldog, as I observe by ex- 

 amination of several crania of each. This has also been shown by 

 De Blainville. It is also seen in the terrier, and in various other 

 races. But in some Saint Bernard crania in the Museum of the 

 Acadeni}' of Natural Sciences, this tooth is more elongate ; and in 

 some of the specimens of Canis lupus from Europe its form is 

 quite the same. So this character, as might have been anticipated, 

 is not of universal application. Another character is seen in the 

 crania of three specimens, which are supposed to belong to Canis 

 terrarius. The superior border of the foramen magnum is inter- 

 rupted by a deep vertical excavation. This is not seen in the St. 



