38 ARKIV FÖR ZOOLOGI. BAND 14. N:0 4. 



The foUowing nine species of Rodents Mr. Oldfield 

 Thomas has kindJy determined: 

 Oryzomys alhigularis Tomes. 



» » maerex Thomas. 



» xantJiaeolus Thomas. 



» barbacoas Allén. 



„ (Melanomys) caliginosus Tomes. 



Sigmodon lönnbergi Thomas. 

 Thomasomys pichincMus Thomas. 

 Proechimys semispinosus Tomes. 

 Ecliimys armatus Geoff. 



Dactylomys dactyliiiiis modestus n. subsp. 



1 J* ^7i2 1919, on the banks of the river Curaray, El 

 Oriente, Ecuador, 1,000 feet. 



In the year 1914 Oldfield Thomas created a new sub- 

 species Dactylomys dactylinus canescens from »below Manaos, 

 Middle Amazons »^ and at the same time he gave his reasons 

 for considering the Upper Amazon region as the type locality 

 of the true D. dactylirius s. str. He added that he had found 

 the characteristic colour pattern of this animal on the spe- 

 cimens from Rio Napo in Brit. Mus., and that also Jentink 

 had identified specimens from Nauta »near Rio Napo» with 

 the typical D. dactylinus. In reality the latter place is situ- 

 ated at Rio Maranon above the mouth of Rio Napo. 



As Rio Curaray is an affluent to Rio Napo from its 

 Southern side, the locality where Consul Söderström has 

 obtained the present specimen is situated almost between 

 the localities for Thomas' and Jentink's specimens, and 

 consequently it ought to be expected that the former would 

 entirely agree with the latter. This is, however, not the case. 



When discussing the colour of the true Dactylomys dac- 

 tylinus Thomas quoted Desmarest's earliest description of 

 1817, and this is of course correct, but Waterhouse^ has 

 fortunately also seen and examined the up to that time (1848) 

 only known specimen and communicated a quitegood descrip- 

 tion of the same. When comparing the specimen from Rio 



I Ann. & Mag. N. H. (8) XI, p. 87. 



- Nat. Hist. of the Mammalia, Vol. II Rodentia. London 1848, p. 311. 



