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TEE AMERICAN NATURALIST [Vol. XLVII 



VII. There is a distinct inheritance of the tendency to 

 produce a greater number of pairs, the correlation being 



VIII. There is no evidence of lateral inheritance of the 

 mammae, the inheritance by pairs being a more probable 

 hypothesis. 



IX. No definitely Mendelizing units were found in the 

 abdominal mammary series, but the relations between 

 grandparents and offspring and parents and offspring, 

 do indicate a segregation of some sort. 



X. Eudimentaries in the functional mammary series 

 have the same*effect on the pattern as normal mammae, 

 and probably represent lack of development. There is 

 no greater tendency to variation among the rudimentary 

 nipples of the male than among the potentially func- 

 tional nipples of the female. 



XI. The paired rudimentaries to the rear of the ingui- 

 nal pair behave as a simple Mendelian unit-character, 

 sex-limited in inheritance. 



LITERATURE CITED 



1894. Materials for the Study of Variation. 

 Creighton, Chas. 



1877. Development of the Mamma; and Mammary Functions. Journal 

 Anat. and Phys., XI, p. 22. 



Klaatsch, H. 



1884. Zur Morphologie der Saugethier Zitzen. Morph. Jahrbuch, Bd. 9. 



1893. Beitrag zur Entwicklungs geschichte der Milchdriisen. Verh. d. 



Phys. Med. Ges. su Wurzburg, XXVI, p. 171. 

 Wentworth, E. N. 



1912. Another Sex-limited Character. Science, N. S., Vol. XXXV, 



No. 913, p. 986. 



Inheritance of Mamma; in Swine. American Breeder's Associa- 

 tion, Vol. 8, 1912. 

 Williams, W. Roger. 



1891. Polymastism with Special Reference to Mamma; Erratic*, etc. 

 Journal Anat. and Phys., XXV, p. 225. 



