_Mammalia._--There seems to be only one genus absolutely peculiar to this sub-region--the very remarkable _Condylura_, or star-nosed mole, only found from Pennsylvania to Nova Scotia, and as far as about 94° west longitude. It also has opossums (_Didelphys_) in common with California, and three out of four species of _Scalops_, a genus of moles; as well as the skunk (_Mephitis_), American badger (_Taxidea_), racoon (_Procyon_), pouched rat (_Geomys_), beaver rat (_Fiber_), jumping mouse (_Jaculus_), tree porcupine (_Erethizon_), and other characteristic Nearctic forms. _Birds._--The birds of this sub-region have been carefully studied by American naturalists, and many interesting facts ascertained as to their distribution and migrations. About 120 species of birds are peculiar to the east coast of the United States, but only about 30 of these are residents all the year round in any part of it; the bird population being essentially a migratory one, coming from the north in winter and the south in summer. The largest number of species seems to be congregated in the district of the Alleghany mountains. A considerable proportion of the passerine birds winter in Central America and the West Indian Islands, and go to the Middle States or Canada to breed; so that even the luxuriant Southern States do not possess many birds which may be called permanent residents. Thus, in East Pennsylvania there are only 52, and in the district of Columbia 54 species, found all the year round, out of about 130 which breed in these localities; very much below the number which permanently reside in Great Britain.