Zoological Society. 483 



sand, and now and then turns round and protrudes its head out of 

 the new-made burrow. It was then our only chance to shoot them, 

 and if not killed on the spot^ there is no hope of obtaining them. 

 Only in one or two instances do I remember seeing them leave their 

 holes to feed on the grass. I think you will find this animal distinct 

 from all the other South American Rodents, and perhaps it will form 

 the type of a new genus. Its native name is 'Tufo' and ' Tojo/ 

 pronounced ' Tu-fo ' and ' To-ko.' 



** 3. A large Mouse, with soft fur and large ears*. This charming 

 little animal we found in the same locality as the above, inhabiting 

 the abandoned caves of the former species. It makes its appearance 

 in the afternoon, when the sun is nearly on the horizon, to feed on 

 grass, and is often seen sitting on its hind legs ; and it then presents 

 its pretty white abdomen and erect ears. In this position it has the 

 appearance of a rabbit in miniature. The natives call it ' Achohalla/ 

 pronounced * Ha-cho-ha-ya.' 



" I have taken the Didelphis Azara with a litter of eight young 

 ones. I have not forwarded this animal with the others ; it will re- 

 main till my return to Chile ; also several species of Mice and Bats. 



" In ornithology I have been very successful, having obtained 

 about 100 species differing from the birds of Chile. I have found 

 a considerable portion of the birds figured in D'Orbigny's splendid 

 work, and before I leave Bolivia I hope to obtain the greater part, 

 especially as in a few days I intend leaving Cochabamba and tra- 

 velling down the river Mamore towards the frontiers of Brazil, 

 traversing the country of the Yaracares Indians, where D'Orbigny 

 found an immense number of novelties. 



*' Amongst the Perdicarce I have found a beautiful species of En- 

 dromia, differing from E. elegans of D'Orbigny ; also a third species 

 of Tinachorus, much larger than T. D' Orbignyanus ; and in the valley 

 of Cochabamba and mountains in the vicinity I have of late had the 

 good fortune to take three distinct species of Nocthura, all of beauti- 

 fully marked plumage, and different from N. Perdicaria of Chile. 

 These have given me excellent sport. Amongst many other inter- 

 esting birds which I have lately taken, I have found Serrirostrum 

 carhonarium and sittoides. My intention is, before I leave Cocha- 

 bamba, to write a communication to the Zoological Society, having 

 now the honour to be a Corresponding Member, giving them a brief 

 idea of what I have accomplished since I arrived in this country. 

 I have no doubt that the Earl of Derby and the Messrs. Gray will have 

 much pleasure at the sight of the Bolivian birds when they arrive in 

 England. I have many interesting insects, amongst which there are 

 three species of Nyctelia and two or three of the genus Phanaus, with 

 others which I am sure will afford you pleasure and amusement.'* 



Hesperomys boliviensis. Hesp.pallide ochraceus, corpore suprcL 

 fusco-penicillato, subtus albo ; pedibus albis flavo-lavatis ; caudd 

 quoad longitudinem corpus fere aquante, albd, suprdflavd: auri- 

 bus permagnis, extus rufescenti-flavis. 



* Hesperomys boliviensis, a new species hereafter described. — G. R. W. 



