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THE AMERICAN NATURALIST [Vol. XLII 



sexual and geographic variation. Forty years ago systematic 

 work was almost wholly analytic, and especially so in respect 

 to the mammals, birds and reptiles of this continent. In my 

 paper "On the Mammals and Winter Birds of East Florida, 

 with an examination of certain assumed specific characters in 

 Birds," etc., published in April, 1871, 3 the conclusions arrived 

 at respecting "species" and specific characters are thus sum- 

 marized : 4 



" (1) That the majority of nominal species originate in two prin- 

 cipal sources of error, namely, (a) an imperfect knowledge of the 

 extent and character of individual variation, and (6) of geographical 

 variation. (2) That this imperfect knowledge is mainly due to the 

 neglect of zoologists to study with sufficient care the common species 

 of their respective countries, whence has arisen a faulty method of 

 investigation and erroneous ideas respecting species and specific char- 

 acters. (3) Instead of the method at present pursued by a large school 

 of descriptive naturalists- the analytic, or the search for differences- 

 being the proper one, that synthesis should be duly combined with 

 analysis, and that general principles should be sought as well as new 

 forms, or so-called ' new species > and ' new genera: (4) It is claimed 

 that nothing is to be gained by giving binomial names to climatic or 

 other forms, in cases where, however considerable the differences be- 

 tween them may be, a complete transition from the one to the other can 

 be traced in specimens from intermediate localities, notwithstanding the 

 plea sometimes urged that their use affords 'convenient handles to 

 facts.' » 



No 3 of these conclusions, 5 here italicised, denotes the class 

 of research exemplified by Dr. Ruthven's monograph. His 

 method of approach to the problem before him is thus stated : 



" Three steps are necessary to determine the genetic relationships and 

 simplify Cope's elaborate arrangement of the group: (1) The value of 

 i Bull. Mus. Corny. Zool., Vol. II, No. 3, pp. 161-450. 

 * L.c, p. 163. 



later adoption of trinomials. In 1872 (Bull. Muf. Comp. Zool., Vol. Ill, 

 Xo. 6, pp. 119 ct $eq., July, 1872) varietal names were advocated and sys- 



