Allen, New South American Muridce, etc. 49 



Phyllotis cachinus, sp. nov. 



Type, No. 97-5-5-19, British Museum, $ adult, Upper Cachi River, Salta, 

 Argentina, collected and presented by Prof. Spegazzini. 



Similar to P. griseoflavus in general coloration, but with the pelage of the 

 ventral surface pale grayish at extreme base, instead of deep plumbeous for the 

 basal half or more. It also differs from P. griseoflavus in the skull being 

 broader, including both the brain case and the rostral portion, with very much 

 heavier dentition, the molar series being one-third broader as well as longer, 

 and with a much heavier lower jaw. 



It differs from P. chacoensis in its shorter parietal (11X3 as against 11X4 in 

 P. chacoensis), heavier dentition, more inflated bullae, and smaller size. 



Measurements (of type). Total length, 296 mm. ; head and body, 137'; tail, 

 159 ; hind foot, 29 ; ear, 24. 



Skull about as in P. griseoflavus and P. chacoensis, except in its rather 

 greater relative breadth as compared with the former, and its short interparietal 

 as compared with the latter, and much heavier dentition in comparison with 

 either. Total length, 35 ; basilar length, 27 ; zygomatic breadth, 17 ; mastoid 

 breadth, 14.5 ; interorbital breadth, 5 ; length of nasals, 15.5 ; palate, 6.8 ; 

 palatal foramina, 7.2X2.5 ; interparietal, 11X2.8 ; upper toothrow, 5.4 ; lower 

 jaw (inner base of incisors to condyle), 19 ; height at condyle, 9 ; lower tooth- 

 row, 5.7. 



A specimen from the Lower Cachi, No. 79-5-5-18, ?, from 

 the same collector, with an imperfect skull, seems better refer- 

 able to P. chacoensis, it having the ventral pelage snow-white to 

 the roots, and weaker dentition. 



Doubtless griseoflavus, chacoensis, and cachinus will prove to be 

 closely related forms of the same species, but they show features 

 of difference worthy of note, and, moreover, inhabit quite differ- 

 ent faunal districts. The first two are chaco forms, widely sep- 

 arated geographically, while the latter is from the mountain 

 district northwest of Salta. 



Eligmodontia morgani, sp. nov. 



Type, collector's No. 127, $ adult, Arroya Else, Patagonia, April 17, 1895; 

 coll. A. E. Colburn. 



Pelage very full, long, and soft. Above dull ochraceous gray, finely lined 

 with black, sides paler and more buffy, passing into a well-defined pale yellow- 

 ish lateral line, extending from the sides of nose to the base of the tail ; lower 

 parts pure white, the fur plumbeous at base, the apical half white ; ears me- 

 dium, dusky brown externally, pale buffy gray internallv ; tail about as long as 

 had and body, sharply bicolor, dark brown above, grayish white below, well 



