MAMMALIA. 
83 
These little animals are exceedingly numerous in the central parts of Chile. 
They frequent by hundreds the hedge-rows and thickets, where they make bur- 
rows close together, leading one into another. They feed by day in a fearless 
manner ; and are very destructive to fields of young corn ; when disturbed, they 
all run together towards their burrows in the same manner that rabbits in England 
do when feeding outside a covert. When running they carry their tails high up, 
more like squirrels than rats ; and they often remain seated on their haunches, 
like the former animals. According to Molina* they lay up a store of food for 
the winter, but do not become dormant. The Octodon is the “ degu” of that 
author : he says that the Indians in past times used to eat them with much relish. 
These animals appear to be very subject to be piebald and albinos ; as if partly 
under the influence of domestication. 
Genus — ABROCOMA.t 
Dentes primores f acuti, eradicati, anticb Iceves : molares utrinque * subcequales , illis 
maxillce superioris in areas duas transversales ob plicas vitreas acutb indentatus 
divisis ; plicis utriusque lateris vix cequb profundis ; illis mandibulce inferioris in 
tres partes divisis, plicis vitreis his interrib, semel externe indentatis, area primd 
sagittce cuspidem Jingente , cceteris acutb triangularibus. 
Artus subcequales. 
Antipedes Udactyli, externo brevissimo, intermediis longissimis et ferb cequalibus. 
Pedes postici 5-dactyli; digito interno brevissimo. Ungues breves et debiles, illo 
digiti secundi lato et lamellari ; omnibus setis rigidis obtectis. 
Caput mediocre, auribus magnis, membranaceis ; oculis mediocribus. 
Cauda breviuscrila. 
Vellus perlongum, et molle. 
The genus Abrocoma is evidently allied on the one hand to the genera Octo- 
don, Poephagomys, and Ctenomys, and on the other to the family Chinchillidce. 
The four genera just mentioned possess so many characters in common, that it 
would be well to unite them, and the name Octodontidce may be used to designate 
the group. 
The Octodontidce appear to bear the same relations to Echimys, as the Arvi- 
colce do to the Muridoe. 
* Compendio de la Hist. Nat. del Reyno de Chile, vol. i. p. 343. 
t 'A/3 pos, soft ; Kofir], hair. 
