420 Mr. 0. Thomas on 



larger than in budini. Cheek-teeth of medium size, smaller 

 than in budini. 



Dimensions of the type : — 



Head and body 182 mm.; tail 117; hind foot 29*5; 

 ear 23'2. 



Skull : greatest length 45 ; condylo-incisive length 42'2 ; 

 zygomatic breadth 23-6 ; bimeatal breadth 24 ; nasals 16"5 ; 

 interorbital breadth 7*4; palatilar length 20; diastema 13; 

 length of bulla on a line parallel with the median axis of the 

 skull 15 ; upper tooth-series, crowns 9*3, alveoli 10. Incisors 

 smaller and more delicate than in budini, about as in cinerea. 



Hub. Famatina Range, Rioja. Type from La Invernada, 

 3800 m. 



Type. Adult male. B.M. no. 20. 8. 4. 46. Original 

 number 960. Collected 19th March, 1920. 



This Famatina Abrocoma is probably most nearly allied to 

 A. budini of Otro Cerro, Catamarca, but is smaller, with 

 shorter muzzle and shorter tail. A. cinerea of Casabindo, 

 Jujuy. has a still shorter tail and shorter feet, and the muzzle 

 is as long as in budini. All these Argentine species, from 

 the eastern slope of the Cordilleras, have the posterior palatal 

 foramina minute, while in the two species of the western — 

 Chilian — .side these foramina are fused into a comparatively 

 large single opening. 



Sr. Budin has been peculiarly successful in obtaining these 

 rare and interesting animals, this being the third he has 

 discovered out of the five species known. 



7. Ctenomys famosus, sp. n. 



cJ. 946, 992, 993, 994, 1013 ; ?. 914, 953, 990, 999, 

 1002. La Invernada and Potrerillo. 



Like C. colndo, but tail shorter and bullae smaller. 



Size about as in coludo, or perhaps a little smaller, but 

 differences of age make exact size-comparison difficult. 

 Colour quite as in that animal. Tail decidedly shorter, the 

 Ion crest of the series only attaining 73 and 74 mm., while in 

 our eight specimens of coludo all adults have the tail over 

 80 mm., while the longest attain 95 and 97. 



Skull very much as in coludo, but smaller. Bullae de- 

 cidedly smaller, though still larger than in the larger species 

 C. knighti of Otro Cerro. Zygomata less widely expanded 

 mesially. Supraorbital region with small ledges. Teeth 

 rather less heavy than in coludo. 



Dimensions of the type : — 



Head and body 160 mm. ; tail 74 ; hind foot 31*5. 



