368 References 



Sears, P. B., and Kathryn H. Clisby. 1952. Two long climatic records. 

 Science 116:176-178. 



Seevers, C. H. 1957. A monograph on the termitophilous Staphylinidae. 

 Fieldiana, Zoology, 40:1-334. 



Serra, J. A. 1958. Chromosomic units of genetic determination. Revista 

 Portug. de Zoologia e Biologia Geral 1:131-195, 219-271, 273-291. 



Shantz, H. L. 1956. History and problems of arid lands development, in 

 The future of arid land. Amer. Assoc. Adv. Sci., Washington, D.C. 



Shelf ord, V. E. 1913. Animal communities in temperate North America. 

 Geog. Soc. Chicago Bull. 5:1-368. 



. 1926. Naturalist's guide to the Americas. Williams and Wilkins 



Co., Baltimore. 



. 1951. Fluctuation of non-forest animal populations in the upper 



Mississippi basin. Ecol. Monog. 21:149-181. 



, and W. P. Flint. 1943. Populations of the chinch bug in the 



upper Mississippi valley from 1823 to 1940. Ecology 24:435-455. 

 , and S. Olson. 1935. Sere, climax and influent animals with spe- 



cial reference to the transcontinental coniferous forests of North 

 America. Ecology 16:375-402. 



Shrock, R. R., and W. H. TwenhoflFel. 1953. Principles of invertebrate 

 paleontology. 2nd ed. McGraw-Hill Book Co., Inc., New York. 



Sibley, C. G. 1950. Species formation in the red-eyed towhees of Mexico. 

 Univ. Calif. Publ. Zool. 50:109-194. 



. 1954. Hybridization in the red-eyed towhees of Mexico. Evolu- 

 tion 8:252-290. 



. 1960. The electrophoretic patterns of avian egg-white proteins 

 as taxonomic characters. Ibis 102:215-284. 



, and D. A. West. 1958. Hybridization in the red-eyed towhees 



of Mexico: the eastern plateau populations. Condor 60:85-104. 



Simpson, G. G. 1940. Antarctica as a faunal migration route. Sixth Pacific 

 Sci. Cong. Proc. 2:755-768. 



. 1944. Tempo and mode in evolution. Columbia Univ. Press, 



New York. 



. 1947. Holarctic mammalian faunas and continental relationships 

 during the Cenozoic. Geol. Soc. Amer. Bull. 58:613-688. 



. 1949. The meaning of evolution. Yale Univ. Press, New Haven. 



