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ORIGIN, ETC., OF THE FAUNA AND FLORA OF 
CENTRAL AMERICA. 
{Tuer following summary and conclusions on the origin and geographical distribution 
of the Mammalia, Reptilia, Batrachia, Pisces, Arachnida, Chilopoda, Diplopoda, and 
Prototracheata of Central America, and the faunistic divisions of the region, have been 
kindly supplied by Messrs. R. I. Pocock and C. ‘Tate Regan; and Mr. W. B. Hemsley 
has given us a similar account of the Flora. These valuable contributions are based 
upon our present knowledge of the subject, bringing the account up to date. As 
regards the Insecta, which occupy so large a portion of the work, no satisfactory con- 
clusions can be formed till they have been more thoroughly collected and studied in 
other tropical regions, and perhaps till we know more of them in a fossil state.-—Eb. | 
FAUNA. 
MAMMALIA. 
By R. I. Pococx, F.R.S. 
Since the publication of Mr. E. R. Alston’s volume on the Mammalia of Central 
America in 1882, great advances have been made in our knowledge of the subject. 
The past history of many of the orders and families has been more or less accurately 
ascertained by paleontological research, principally in the United States and in the 
Argentine; and the modern methods of collecting and preserving existing material 
have led to the discovery of Jarge numbers of genera, species, and subspecies, and 
in addition have thrown such light upon the vertical and horizontal distribution of 
American Mammals, as a whole, that it has become possible to map their zones and 
provinces with much greater precision. 
This progress in accuracy of information has been accompanied by a gradual change in 
the conception of systematic terms, with the result that what our predecessors ignored 
as “local varieties” are now regarded as “species ” and, by a logical sequence, the old- 
time species are being given the rank of genera. Quite apart, too, from the names 
that have been introduced to designate new forms, considerable changes have taken 
place in the nomenclature of long-established species and genera. Opinions may differ 
as to the advisability and advantage of the alterations coming under these headings, but 
they have to be admitted and dealt with by faunistic and systematic workers. 
