1909.] R. E. L1.0YD : The Races of Indian Rats. 13 



custom at the present day, when the species of twenty years ago 

 rank as genera, and new species must be found. 



Within the last few months a revision of the genera Gunomys, 

 Nesokia and Bandicota has been published [11], including several 

 new species. As the specific characters are founded on the measure- 

 ments of chance-taken '' types," it is impossible to identify our 

 specimens by means of this classification. The difficulty of attempt- 

 ing to do so may be briefly expressed. In this new classification 

 nine species of Gunomys are recognised. They are divided into two 

 series, A with upper molars less in length than 7*5 mm., B with 

 upper molars greater than 7*5 mm. 



The length of the upper molars in twenty mature specimens 

 of Gunomys from Calcutta — presumably G. bengalensis^vary from 

 6*5 to 8 mm. (Hossack). The measurements of the molar series in 

 the types of the nine species of Gunomys are, according to this new 

 classification, as follows: Series A, 6-6, 6-8, y2, 7*6, yd)\ Series B, 

 8j8, 8*3, 8'3. We see therefore that as regards the length of the 

 molars, which is so important a character that it is used in the 

 grouping of the species, twent}^ chance-taken specimens from 

 Calcutta include no less than seven out of the nine Oriental species 

 of the genus. The skulls from which Hossack's measurements 

 were taken are preserved in the Indian Museum ; the accuracy of the 

 measurements cannot be questioned. 



On the average the Gunomys of the Punjab certainly have 

 larger teeth than the Gunomys of Bengal, but the measurements 

 given in the new classification are of chance-taken " types," and 

 variation among the rats of any district is so wide that none of the 

 characters quoted can be relied upon for identification. The onh' 

 reliable datum is the name of the district from which the " types" 

 were obtained. We know from this that our specimens from 

 Kashmir and Nepal are G. wardi and tarayensis , respectively. If 

 this method is permissible identification is easy, but the number of 

 species must be large. 



It is unfortunate that the author of this classification did not 

 consult Hossack's work ; if he had done so he would have avoided 

 the error of supposing that the Gunomys of Bengal measures 205 

 mm. in length. Hossack's measurements of fifty specimens from 

 Calcutta show that the length of this species varies from 160 to 

 205 mm., with a mean of 182. Specimens measuring over 200 mm 

 can be found only with difficulty. 



MEASUREMENTS AND DEFINITIONS. 



Before passing to the descriptive portion certain terms must 

 be defined — 



I. By the length of a rat is meant the combined length of 

 its head and body, i.e., the distance between the 

 snout and anus ; the difficulty of measuring it ac- 

 curately has been already mentioned. For the sake 

 of brevity measurements have been recorded without 



