88 ^I>"- 0. Tliomas on 



specimen o£ Echimys dactylinus, Desm., was witliout locality, 

 and the several descriptions of different dates do not entirely 

 agree with each other — probably owing to the progressive 

 deterioration and bleaching of the type specimen. 



Taking for this reason tlie earliest account as the most 

 valid, we have tlie two by Desmarest* in 1817 and 1822, in 

 which it is clearly stated that the animal was " jaunatre sur 

 le dos " and " presque roux f sur les flancs," tlie latter being 

 the most characteristic mark of the Eio Napo specimens in 

 the British Museum as compared with the skin from Itacoa- 

 tiara. I therefore propose to consider the Upper Amazon 

 animal as true dactylinus^ and that from the river lower down 

 as a new form. 



This would also fall in with Dr. Jentink's identification of 

 his specimens from Nauta (near the Kio Napo) as D. dacty- 

 linus. 



Loncheres grandis, Wagn. 

 (^. 21 ; ? . 24. Parana de Faro {Oscar Martins). 



Loncheres armatus, Geoff. 

 S . 20. Parana de Faro {0. Martins). 



Isothrix pagurus, Wagn. 



^ . 3. Boim, Rio Tapajoz [E. Stiethlage). 



As has happened with several members of the present 

 family, this species was described from a specimen which 

 had lost its tail, and as it has never been rediscovered until 

 now, the present is the first perfect specimen ever recorded. 

 The tail is longer than the head and body, uniformly clothed 

 beyond the basal inch with soft hairs 7-8 mm. in length, not 

 specially lengthened at the tip. The base is, as usual, 

 coloured like the body ; then follows a short zone (an inch 

 above and three below) of dull buffy, the remainder, above 

 and below, being blackish proximally and brown terminally. 



The original specimen, a female by the description, though 

 referred to as a male, was obtained by Natterer at Borba, on 

 the Lower Madeira, about 300 miles west of the present 

 locality, in 1830, and described by Wagner in 1845. It is 

 now in the Vienna Museum, where I have examined it. 



* N. Diet. d'H. N. (2) X. p. 57 (1817) ; Mamm. ii. p. 291 (1S22). 

 t The early PVench authors always described as "roux" what we 

 should now call '' buff," not any colour we should look upon as "red." 



