Cope.l O [May 16, 



make a comparison of his plate and the Peruvian jaw, with a well pre- 

 served jaw of the D. humboldtii, with perfect last molar and symphysis, 

 from Buenos Ayres, in my collection. I am able fully to substantiate the 

 characters already pointed out by Gervais, and to prove that the cross- 

 crests of the molars form double trefoils, while those of the D. tropicus 

 are like those of D. shepardi and the Tetrabelodon andium. 



The species last named is said by Falconer (loc. sup. bit.) to occur in 

 Mexico, and speaks of having seen a well preserved lower jaw from the 

 State of Tlaxcala. I have not met with it. 



The Mastodon americanus has not yet been found in Mexico. The most 

 southern localities for the species known to me are Southern California, 

 and near San Antonio, Texas. From the former region I possess a ramus 

 with the last molar, presented to me by Mr. Scupham, of San Francisco ; 

 the other specimen was obtained from Mr. G. W. Marnock, of Helotes, 

 near San Antonio, Texas. 



ELEPHAS Linn. 



Elephas PRiMiaENius Blum. 



This species, of both the thick and thin plated varieties, was once very 

 abundant in Mexico. I have received a series of teeth from Candela, in 

 the State ot Coahuila, from Dr. Caspar Butcher, through my friend Dr. 

 Persifor Frazer ; and Von Meyer has pointed out the occurrence of its re- 

 mains in the valley of Mexico. The museums of Mexico contain very 

 numerous portions of skeletons of this species, which prove that it was 

 far more abundant than the species of Mastodon. Up to this time this 

 locality is the southern known limit of its distribution on the American 

 continent. 



APHELOPS Cope. 



Aphelops, sp. Aphelops ? fossiger Cope. Proceedings Academy Phil- 

 adelphia, 1883, p. 301. 



The right half of the mandible, with part of the symphysis of a rhinoc- 

 eros, was found in the valley of Toluca, sixty miles west from the city of 

 Mexico, and Dr. Barcena sent me a photograph of it a year ago. I pub- 

 lished a notice of it as above cited, in connection with remarks on a rhi 

 noceros skull which I obtained on one of the heads of the Gila river in 

 New Mexico. On my recent visit to the College of Toluca, I had, through 

 the kindness of Professor Yillada, the opportunity of examining the jaw. 

 Its characters do not differ much from those of the Aphelops fossiger Cope. 

 It is considerably smaller, and has a very short diastema, but not shorter 

 than in some jaws of the A. fossiger. The dimensions are as follows : 



Measurements. M. 



Length of ramus from base of canine 400 



" " dental series with canine, less M. iii 235 



" " molar series, less M. iii 200 



" " true molars, less M. iii 105 



