764 THE AMERICAN NATURALIST. [VoL. XXXIV. 
affected that no rules can be laid down for its use, though it is cer- 
tainly less of a decolorizer than alcohol. Its considerable antiseptic 
and toxic properties are finally described. P. 
Jordan and Evermann's Fishes, Part IV.! — The last volume of 
this great work has just been issued. It contains the additional 
Addenda and the plates illustrating nearly one thousand species of 
American fishes. This entire work is in one sense a revision of 
* Synopsis of Fishes of North America" (Bulletin No. 16), by 
Jordan and Gilbert. Bulletin No. 16, however, included only the 
fishes then known to inhabit North America north of the Tropic 
of Cancer. Aside from the Addenda, it forms one volume of 866 
pages and records 1339 species. The Addenda contain 108 more 
pages, which adds about 160 more species. The volume contains 
no plates. The present work includes all salt-water fishes which 
inhabit America north of the equator, and all fresh-water fishes 
north of the Isthmus of Panama. Aside from the Addenda, the 
work contains 2744 pages and describes 3127 species of fishes. 
The Addenda in Vol. III contain 130 pages, and Vol. IV has an 
additional Addenda of 160 pages. Vol. IV also includes a com- 
plete table of contents for all species listed in the four volumes. 
“From this systematic arrangement it is seen that the fish fauna 
of North and Middle America, as now understood by the present 
authors, embraces 3 classes, 30 orders, 225 families, 1113 genera, 
325 subgenera, 3263 species, and 133 subspecies." This is by far 
the most extensive and most useful work.ever written on American 
fishes. It contains descriptions of all the species known from the 
region which it covers and analytical keys to facilitate identification. 
Atterition is often called to doubtful species in footnotes, and in 
many cases the original description is given. This tendency not to 
place in synonymy doubtful species, when chances are even that 2 
careful study will prove them valid, is to be commended. It will no 
doubt require a careful study of variation to dispose properly of 
many doubtful species and many subspecies. It is best to let them 
stand as first indicated until this sort of study can be made. The 
next century will witness a great deal of study of the variation of 
animals, which, with its complement of morphological study, will 
eventually reduce the work of the classification to a proper basis. 
Jordan, D. S., and Evermann, B. W. The Fishes of North and Middle 
1 
America, Bull. U. S. Nat. Mus. (1900), Pt. iv, No. 47, ci + 3137-3313 PP» 
392 plates. 
