1904.J RODENT OmOMYS BRANICKII. 159 



scientific event that has occuiTed (hiring tlie first decennium of 

 the existence of the Para Museiim, after the refinding of the 

 long-lost Dipnoan Lepidosiren paradoxa, as fully described in 

 former vohimes of the Zoological Society's publications. 



My svirprise was unbounded when, a few weeks ago, I received 

 from a fidend of the Museum, personally unknown to me, a cage 

 containing a paii- of live large Rodents entii'ely new to me, 

 notwithstanding a twenty years' acquaintance with the Brazilian 

 fauna, both from the South and the ISToi'th. These, after a 

 quarter of an hour of eager consultation of the more modern 

 manuals of mammalogy, I recognised as being identical with the 

 almost legendary Dinoinijs branickU, of which science had lost 

 sight for thirty yeai's. 



It seems to me to be a most opportiine occasion to publish a 

 short description of the external features and the habits of Dinomys, 

 as it is pi'obable that the memoir of Prof. Peters, the only source 

 of information on the subject up to the present, is deficient 

 in these particulai-s. A series of photographs of the animal, 

 taken in difierent attitudes spontaneously assumed, supplement 

 my verbal explanations. 



Doubtless the first impression fi-om the genei-al appearance, 

 especially as regards size and external features, would ally the 

 animal closely with the South- American " Paca " (^Agouti paca) ; 

 and the verdict of the scientist as to its systematic location 

 has no reason to difier from the popular conception which has 

 given to our Rodent the local name of " Paca-rana," a Tupy-term 

 meaning " pseudo-paca." In size the older and larger specimen, 

 the mother, is almost exactly of the dimensions of an average 

 Pdca : the young one is approximately half or two-thirds of that 

 size. The similarity is increased by its capacious head, and the 

 brownish coloui' marked with distinctly visible longitudinal rows 

 of white spots. This similarity, howevei-, begins to diminish as 

 soon as one undertakes a more minute examination. It presents 

 first the striking difierence of having a hairy tail of about 2 deci- 

 meti'es in length. Still further, as i-egards the hair, while that of 

 the Paca is soft to the touch and of even length, i-esembling 

 somewhat the fur of the Ottei-, Dinomys has a rougher coat of 

 stifier hairs, uneven in length (these stiffer hairs being white- 

 tipped and longer, and contributing to interrupt the uniformity of 

 the general colour), and forming a first transition-step towards 

 the quills of the coats of the Spiny Rats propei- (Loncheridse, 

 Echinomyidse). The white spots are located only on the rear part 

 of the trunk, beginning fi-om the shoulders. They are sepai-ated 

 in two groups: (1) four longitudinal rows, nearly continuous at 

 the fore part, the median line of the back being dark ; (2) two 

 lateral areas of more or less cu-cular white spots occupying the 

 flanks and thighs, scattei-ed irregularly, as it would seem at first 

 sight, but betraying a tendency to longitudinal arrangement on 

 closer observation. 



The form of the head of Dinotnys may be described as sub- 



