CHAP. XVII.] 
MAMMALIA. 
239 
of Panama. The genera are as follows : — Dactylomys (2 sp.), 
Guiana and Brazil ; Cercomys (1 sp.). Central Brazil ; Lasiuromys 
(1 sp.), San Paulo, Brazil; Petromys (1 sp.), South Africa; Myopo- 
tamus (X sp.), the coypu, on the East side of the Andes from 
Peru to 42° S. lat., on the West side from 33° to 48° S. lat. ; 
Carterodon (1 sp.), Minaes Geraes, Brazil; Autocodes (1. sp.), 
West and South Africa ; Mesomys (1 sp.), Borba on the Amazon ; 
Echimys (11 sp.), from Guiana and the Ecuadorian Andes to 
Paraguay ; Lonchercs (10 sp.), New Granada to Brazil. 
Fossil and Extinct Echimyidce. — The genus Carterodon was 
established on bones found in the Brazilian caves, and it was 
several years afterwards that specimens were obtained showing 
the animal to be a living species. Extinct species of Myopo- 
tamus and Lonchercs have also been found in these caves, with 
the extinct genera Lonchophorus and Phyllomys. 
No remains of this family have been discovered in North 
America ; but in the Miocene and Upper Eocene deposits of 
France there are many species of an extinct genus Theridomys, 
which is said to be allied to this group or to the next (Cercola- 
bidae). Aulacodon , from the Upper Miocene of Germany, is 
allied to the West African Autocodes; and some other remains 
from the lower Miocene of Auvergne, are supposed to belong to 
Echimys. 
Family 66.— CEECOLABTD.E. (3 Genera, 13-15 Species.) 
General Distribution. 
Neotropical 
Sub-regions. 
. N EARCTIC 
Sub-regions. 
1? A I, .EARCTIC 
Sub-regions. 
Ethiopian 
Sub-regions. 
Oriental 
Sub- regions, 
Australian 
Sub-regions. 
1 
! 1 
The Cercolabidce, or arboreal porcupines, are a group of rodents 
entirely confined to America, where they range from the northern 
limit of trees on the Mackenzie River, to the southern limit of 
forests in Paraguay. There is however an intervening district, 
the Southern United States, from which they are absent. Erc- 
thizon (3 sp.), the Canadian porcupine, is found throughout 
