84 Merriam Rediscovery of the Mexican Kangaroo Rat 



true phillipsi by nearly all writers on the genus during the past 

 half century. 



In studying a large series of kangaroo rats from Texas, New 

 Mexico, Arizona, and California several years ago I was sur- 

 prised to find that none of them conformed with the original 

 description or with Audubon and Bachman's plate and measure- 

 ments taken from the type specimen in the British Museum. It 

 became apparent therefore that true Dipodomys phillipsi was not 

 represented in the extensive collections examined, and probably 

 was not an inhabitant of any part of the United States. Every 

 available means was used to secure specimens from the sup- 

 posed type locality, but without success. Letters were written 

 in both English and Spanish to Mexican officials in Real del 

 Monte describing the animal and offering a reward for a speci- 

 men, and later ah experienced mammal collector was sent to 

 the place, but with no better result. Finally Mr. E. W. Nelson, 

 who has caught hundreds of kangaroo rats in various parts of 

 the United States and Mexico and is thoroughly familiar not 

 only with the habits of the animals but also with the kind of 

 country inhabited by them, was requested to visit the region, in 

 connection with his work for the United States Department of 

 Agriculture. The result is a series of 67 handsomely prepared 

 skins and skulls and several complete skeletons of the long lost 

 Dipodomys phillipsi. Hence, after a lapse of more than fifty 

 years, it is now possible for the first time to redefine the 

 type of the genus and. to differentiate the species from others 

 with which it has been persistently confounded. Before doing 

 this, however, it seems desirable to put on record with some 

 detail the facts connected with its rediscovery and distribution. 



Notes on a Search for Duplicate Types of Dipodomys phillipsi. 



In response to my request, Mr. Nelson has contributed the 

 following interesting account of his search for this species : 



'' After securing specimens of Dipodomys phUKpsi in the Valley of Mex- 

 ico, at Tlalpani, Ajusco, and Amecameca in December, 1892, and February, 

 1893, I finally set out to try and obtain specimens nearer Ileal del Monte, 

 the supposed type locality. A long and careful search in the vicinity of 

 Tula, in Hidalgo, just north of the valley, failed to discover it or any 

 allied species. From that point to Pachuca, along the extreme northern 

 border of the valley, the country presented the same hard, rocky, and 

 unsuitable character found at Tula. Pachuca is situated at the extreme 



