1914.] NATURAL SCIENCES OF PHILADELPHIA. 13 



The series of skins measures as follows: 



Hind 

 Length. Tail. foot. Ear. 



cf, Hacienda Garzon. 10,500 



ft., April 28 250 115 32 17 



9 , Hacienda Garzon, 10,500 



ft., April 28 212 103 29 16 



9 , juv., Hacienda Garzon, 



10,500 ft., April 28 210 100 28.5 15.5 



cf, Hacienda Garzon, 10,500 



ft., April 28 253 115 30.5 15.5 



cf , Hacienda Garzon, 10,500 



ft., May 12 30 15 



9 , Hacienda Garzon, 10,500 



ft.. May 15 250 110 31.5 16 



Mr. Osgood informs me that so far as he is aware all of the de- 

 scribed species approximating this in size have relatively shorter 

 tails, while the blackish back distinguishes it from all those species 

 available for comparison. 



"Several specimens of this mouse were secured above the Casa 

 'Garzon, along the trail from that Hacienda to the summit of Mount 

 Pichincha. The elevation was a few hundred feet above the valley, 

 where the marsupial Ccenolestes was secured, approximately 10,500 feet 

 and probably this is their lowest range, as much trapping was done 

 200 to 300 feet farther down without securing any. Their habitat 

 was on the rocky wooded slopes, where they had burrow^s similar 

 to those of our North American Microtine rodents, from one to 

 three inches below the surface of the soil and debris. 



"I was interested to notice, when skinning these mice, that all of 

 them, or possibly only the males, were supplied with a remarkable 

 prolongation of the anus, that organ being extended, or rather, 

 >extensible, beyond the thighs for half an inch or more, as indicated 

 in the memoranda on the labels of the specimens. This prolongation 

 was not an internal extension, but external, being hairy throughout." 

 (S. N. Rhoads.) 



11. Akodon mollis altorum Thomas. 



Akodon mollis altoruvi Thomas Ann. and Mag. Nat. Hist., 1913 (II), p. 404. 

 (Canar.) 



Nine specimens of this mouse were obtained on the paramo of 

 Pichincha or near Hacienda Garzon, a little lower down. 



Externally they are almost exactly like Thomasomys paramorum, 

 averaging perhaps a little darker or duller, but are easily recognized 

 by the shorter tail. 



