28 Records of Die Indian Museum. [Vol. Ill, 



Nesokia and Gunomys all show that the range of variation in 

 length is about 40 ^o "^ the mean length ; the same is probably 

 true of all small mammals. This is not usually admitted by sys- 

 tematists at the present day, although in 1871 J. A. Allen measured 

 the length of twent}'- eight adult squirrels and found that this com- 

 paratively small number exhibited a range of o\-er 20 % of the 

 mean [12]. 



In the case of Nesokia, however, there is considerable evidence 

 that a pigmy race has arisen or is arising in a certain part of the 

 Amritsar district. Some families of Nesokia were sent from a field 

 near the village of Atari; these included four adults. In length 

 these four measure 146, 147, 151, 155 mm., that is to say, they are 

 all well below the mean. The similarity of the skulls of these four 

 is remarkable. 



The pigmy which measures 134 mm. is, however, from another 

 part of the district. It was specially sent by Davys as it was 

 pregnant, bearing two embryos. The third molars of this specimen 

 are well worn down. Its maturity cannot be questioned. 



Plate ii shows a series of seven Nesokics selected from the 

 twenty-three to show gradation in length. Beneath them are 

 shown the skulls of the same seven specimens. These skulls ex- 

 hibit not onl}^ a difference in size, but a difference in form, for in the 

 two marked S. B. B. i and S. B. B. 18 the ridges which' mark the 

 upper limit of the temporal muscles are visible but not prominent, 

 and are set widely apart. In the skull P. C. M. 2 these ridges are 

 more prominent and much closer together ; this is the skull of the 

 largest Nesokia we have received. The rats designated S. B. B. are 

 the small ones from Atari already mentioned. Other skulls are 

 intermediate in form as well as size between the two extremes. 

 The measurements given below show how the small skulls resemble 

 one another and differ from the larger ones in the proportions 

 of the molar teeth. 



The bodily proportions of Nesokia are shown on plate v. The 

 percentage of the tail length in the length varies from 49 to 60, with 

 an average of about 54. The discontinuity of the two genera is 

 clear ; there is not the slightest upward tendency in the line of the 

 tail proportion {Bt.) shown by the largest Nesokia, although as re- 

 gards length the two races overlap by a wide margin. The percent- 

 age of the hind foot is between 17 and 18, or about i % higher 

 than in Gunomys, but in this character there is a distinct downward 

 tendency in the line shown by: the largest specimens {Bf.). 



The skull of a Nesokia is easily distinguishable from that of a 

 Gunomys owing to the abbreviating of the palatine foramen. The 

 two races are quite discontinuous as regards this character, although 

 they both show considerable variation (plate iii). Although this 

 is the most obvious difference between the two types, it is not 

 the essential one. The teeth, both incisors and molars, are much 

 larger m Nesokia than in Gunomys. We can therefore see a reason 

 for the abbreviation of the palatine foramen which has obviously 

 been caused by the closing of the posterior half of that space. A 



