Mr. 0. Thomas on Putorius ermineus. 451 



LI II. — On the Bepresentatives 0/ Putorius ermineus in 

 Algeria and Ferghana. By Oldfield Thomas. 



While investigating the constancy of the markings and 

 other characters of Putorius ermineus for comparison with the 

 newly discovered P. hihernicus *, the differences presented by 

 certain representatives of the species found on the southern 

 and eastern outskirts of its Old- World range have appeared 

 to me worthy of notice. 



One of the forms to be considered is from Algeria and the 

 other from Ferghana, Central Asia ; and both show a marked 

 reduction in size as compared with typical individuals of the 

 species from Northern Europe, a fact instructive in its bearing 

 on the question as to what is the real centre of distribution of 

 this widely spread animal. But curiously enough, contrary 

 to the usual rule, the southern (Algerian) form is charac- 

 terized by a particularly short tail, while elsewhere, even in 

 the Arctic Regions, the tail is always long. That from Fer- 

 ghana, on the other hand, has the normal proportions of the 

 species, although combined with reduction in size and a colo- 

 ration apparently due to desert influences. 



As tending to oppose the generally received ideas on the 

 relative value of size and proportions as against that of colour- 

 markings, special attention may be drawn to the constancy of 

 the distribution of the markings of P. ermineus amid all the 

 variations found in size, proportions, and actual shades of 

 colour. 



Putorius ermineus algiricus, subsp. n. 



Decidedly smaller than in typicus, with a shorter tail. 

 Colour of back with a much stronger fulvous suffusion, and 

 of belly more markedly sulphur-yellow. Distribution of 

 colours quite as in typicus. Upper lip and chin and edge of 

 ears white. Yellow colour of belly running down inner sides 

 of hind limbs on to the digits, leaving the outer halves of the 

 metatarsals brown. 



Skull small and slender, with a particularly low and narrow 

 brain-case. 



Dimensions of type (an adult female skin) : — 



Head and body 205 millim. ; tail, without hairs 52, with 

 hairs 76 ; hind foot 31"5. 



Skull : length from gnathion to upper edge of foramen 

 magnum 39 ; zygomatic breadth 19*8 ; interorbital breadth 9 ; 

 breadth of brain-case 18 ; height of brain-case above level of 

 * Ann. & Mag. Nat. Hist., Apr. 1895, p. 374. 



