On small Mammals from North-western Rioja. 417 



XLVI. — On small Mammals from the Famatina Chain, 

 North-western Rioja. By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



DURING March and April, after obtaining the collection from 

 Tinogasta of which a list was recently given, Sr. Budin made 

 an excursion to the chain of high hills known as the Sierra 

 Famatina, in the north-western part of Rioja. The chain 

 runs nearly due north and south, approximately on 68° W., 

 and extending from about 28° 20' to 29° 30' S. 



Sr. Budin collected mostly at a place called La Invernada, 

 in the northern half of the chain, about 35 km. north of the 

 mountain " Nevada de Famatina," and situated at an altitude 

 of about 3800 in. A few specimens (numbers above 989) 

 were obtained lower down and further south, at Potrerillo, 

 alt. 1600 m. 



As has happened with several of the collections, the 

 Muridse have proved to belong to known and more or less 

 widely spread forms, while the Octodontidce and Chinchillidse 

 have peculiar local specializations which involve their being- 

 described as new. Thus the present collection contains new 

 forms of Abrocoma, Lagidium, and Ctenomys, all distinct 

 from their nearest known allies. On the other hand, no 

 species of Muridse new to the Museum are in the collection, 

 the one now described as new having been represented here, 

 erroneously determined, for many years. 



1. Phyllotis riearduluSj Thos. 



<J . 908, 911, 913, 924, 931, 933, 936, 937, 940, 942, 975, 

 977, 978, 1006, 1011 j ? . 915, 917, 918, 939, 949, 955, 

 958, 962, 965, 973, 979, 980, 989. La Invernada and 

 Potrerillo. 



2. Graomys caehinus, All. 



<?. 996, 1000, 1001. All from Potrerillo. 



3. Akodon glaucinns, Thos. 

 S . 995 ; ? . 1014. Potrerillo. 



4. Akodon alterus, Thos. 



S. 900, 905, 910, 920, 938, 969, 985, 986, 998, 1003, 

 1004 ; ? . 903, 907, 922, 923, 925, 929, 941, 945, 954, 957, 

 966, 970, 971, 974, 976, 982, 983, 997, 1007, 1008, 1010. 

 La Invernada and Potrerillo. 



Ann. cfc Mag. N. Hist. Ser. 9. Vol. vi. 28 



