No. 424.] NOTES AND LITERATURE. 333 
North American Finches.'— This work, when complete, will of 
course be the standard book of reference on North American birds. 
It represents the matured views of our foremost ornithologist and is 
remarkable for the clear and terse, yet ample, manner in which the 
facts are presented. It includes not merely the birds of the United 
States and Canada, but also those of Central America, Mexico, the 
West Indies, and the Galapagos Islands. A full bibliography is 
given for every species and subspecies; and there are numerous 
measurements of specimens from different localities, indicating 
slightly variant forms not designated by special names. 
The present volume includes the sparrows and finches. Excluding 
the Galapagos genera, and three species introduced from Europe, we 
have 186 species, to which are added 165 subspecies, making 351 
named forms in all. The species may be divided thus: 
I. Monotypic species in monotypic genera . . + - + + Ib 
2. Polytypic species in monotypic genera iva N 
3. Monotypic species in polytypic genera. . =- - + + - 106. 
4. 59- 
Polytypic species in polytypic genera. . + + + + + 
Total monotypic species, 119; polytypic species, 67. 
A monotypic genus is one which has only a single species; a mono- 
typic species is one having only one form, 2.¢., without subspecies. 
The monotypic genera of the first group are distributed thus: 
1. Great plains of North America: Rhynchophanes, Calamospiza, Centronyx. 
2. Mountains of Western North America: Oreospiza. 
3. Mexico and Central America: Plagiospiza, Pselliophorus, Pezopetes, Acan- 
thidops, Rhodothraupis. 
4. Cocos I., off Bay of Panama: Cocornis. 
5. West Indies: Melanospiza (St. Lucia), Loxipasser (Jamaica), Loximitris 
(Haiti). 
It is significant and interesting that there are no monotypic genera 
with monotypic species east of the great plains; or, excepting Oreo- 
spiza, west of them to the Pacific. The conditions in the west, which 
have produced so many distinct species and subspecies, have not yet 
given us, in the groups under consideration, new generic types. In 
other words, the evolution of the peculiar western genera antedates 
the comparatively recent development of local specific forms. ‘This 
agrees very well with the results obtained from the study of other 
groups, eg., the flowering plants. We find numerous closely allied 
1Ridgway, Robert. The Birds of North and Middle America, Part I, Buz. 
No. 50. U.S. Nat. Mus. 1901. 715 pp. 20 pls- -` x 
