196 PROF. J. LOGAN LOBLEY, F.G.S., F.R.G.S., ON 
in the south and the north, and yet the typical genus Mus, or 
true mice and rats, with 130 species, including our own common 
house mouse, Mus musculus, and the brown rat, so abundant in 
London, is not to be found represented by a single indigenous 
species in either North or South America. On the other hand, 
the musk rat, Fiber zibethicus, and the genus Heteromys, are 
confined to the western continent. The jerboas or jumping 
mice have one species in North America, and one of the two 
species of heaver, Castor canadensis, ranges from Labrador to 
Mexico. The squirrels have in all 239 species. Of these 
twelve are in South and 82 in North America, but our lively 
little friend, the English squirrel, Sciurus vulgaris, is absent 
from both. The prairie-dogs, as they are called, Cynomys 
hulavicianus, are altogether American, but the true marmots, 
Arctomys, are both in America and Europe. Of Leporidte, 
hares and rabbits, sixty-one species have been described, and of 
these twenty-five are American, but only one is in South 
America. The common hare of England, the mountain hare 
of Ireland and Europe, and the European rabbit are all three 
absent from America. A species of the picas or tailless hares, 
Lagomys, is found in the Pocky Mountains, and the coypu, a 
large beaver-like water rat, Myopotamus coypu, is well known in 
Peru and Chili. The family of rodents called Octodontidte has 
sixty-eight species in the Neotropical region, and of these 
twenty-nine are peculiar to the West Indies. 
The order Edentata has three families out of five in 
America, but all the three, comprising thirty-four species, are 
confined to Southern and Central America, or the Neotropical 
region. They are some of the most characteristic American 
animals. The sloths, forming the Bradypodidse, and the ant- 
eaters forming the Myrmecophagidte are arboreal, and inhabit 
the great forests of South America, but the armadillos, forming 
the Dasypodidte, range throughout the Neotropical region. 
The marsupials have a remarkable distribution, since they are 
confined to the Australian region and America, and of the 
thirty-nine genera comprising the order only two are to be 
found in America. These are Didelphys, with twenty-five 
species of opossums, and Chironectes, the water opossum. All 
except one species, Didelphys calif ornica which is in Mexico 
and California, are inhabitants of the Neotropical region. 
The lowest order of Mammalia, Monotremata, is altogether 
absent from the American continent, as it is from all the other 
zoogeographical regions except Australia. 
