142 HEREDITY IN RELATION TO EUGENICS 



Abnormalities in excess number of teeth are also found. 

 Tomes refers to the occurrence of "well defined additional 

 lingual cusps in the upper molar" in both "father and his 



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Fig. 116. — Pedigree of family with faulty enamel of the teeth — "brown 

 teeth." Numbers below, or inside of, symbols indicate the number of individ- 

 uals of the sex and condition of teeth. With one possible exception affected 

 persons have at least one affected parent. Spokes, 1889. 



children." An American family with whom the writer has 

 corresponded has a double set of permanent teeth as a 

 family trait. 





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Fig. 117. — Pedigree of hypoplasia of enamel in Thrower- Walsingham- 

 Chesbtjm family of Ware, England. I, 2, original parents of strain; TI, 1, at the 

 age of 84 two stunted teeth in the upper jaw; III, 6, two stunted upper teeth; 

 III, 7i at 51 years has the fourth upper right and fifth lower teeth brokeii 

 down; IV, 6, some teeth never erupted; some broken down; IV, 9, at 30 some 

 teeth small, some never erupted. This dental peculiarity appears only in the 

 offspring of an affected parent, consequently it is a positive trait. Turner 

 1907. 



More complete are the studies made on families with 

 faulty enamel of the teeth. In Fig. 116 is given the case of 

 ''brown teeth" due to faulty enamel. In Fig. 117 is given 



