242 Mr. 0. Tliomas on 



Skull small, narrow, not particularly flattened ; U|)per 

 profile slightly and evenly convex ; nasals parallel-sided or 

 evenly narrowing backward. Posterior width on edge of 

 meatus greater than the zygomatic breadth. Bullae large and 

 evenly inflated. An indication of a groove on the upper 

 surface of the malar in one specimen, not perceptible in the 

 others. Palate ending opposite penultimate molar. Ecto- 

 condyloid processes of lower jaw well defined, though small. 



Dimensions of the type : — 



Head and body 190 millim. ; tail 74 ; hind foot, s. u. 28, 

 c. u. 32 ; ear 7. 



Skull : greatest length in middle line 39 ; basilar length 

 33*5 ; zygomatic breadth 24'7 ; nasals 13*1 x 6*2 ; least 

 breadth across brain-case 16 3 greatest breadth on meatus 

 256; palate length 17 j diastema lO'l; length of molar 

 series (alveoli) 8; bullae 14x7'3; least breadth of basi- 

 occipital 2"3 ; greatest breadth across lower jaw 32. 



The basilar length of the female skull is 304. 



Type. Old male. B.M. no. 2. 2. 5. 21. Original number 

 1693. Killed 25th November, 1901. 



This species is half as large again as Dr. Nehring's 

 C. Piaidti, smaller than C. mendocinus, and is also distin- 

 guished from both by its dark frontal region. 



I have named it in honour of Dr. Carlos Berg, Director of 

 the Buenos Ayres Museum, one of the first zoological ex- 

 plorers in the salina district, and the discoverer of Dolichotis 

 salim'cola, Burm.* 



10. Dolichotis magellamcus centricoJaj subsp. n. 



a, h. (J ? . 2nd December, 1901. 



Similar in size and general characters to the typical form 

 of Patagonia and Southern Argentina, but the dorsal colour 

 is of rather a clearer and more bluish tone, the fulvous of the 

 cheeks, sides, and thighs is paler and more sandy, the hairs 

 of the ears are sandy and less black, the claws are rather 

 more sharply keeled and compressed, and, finally and chiefly, 

 the dorsal colour is not edged with black behind, the grey 

 passing down without darkening to meet the white of the 

 lower rump. 



The last-named character is my chief reason for distin- 

 guishing the northern form of the Greater i\lara from the 

 southern. Six specimens of the typical form all have the 

 well-known black marking, edging and showing up the white 



* Since the above was written news lias arrived of the deatli of 

 Dr. ]5erp, to the very dt-ep icgrit of all ■who had the pleasure of his 

 acquaintance. 



