INDIVIDUAL AND SEXUAL VARIATION. 605 



sometimes thick and short and again slender and very long 

 These variations are all as strongly marked in the young killed 

 a few days after birth as in the adult, showing that the varia- 

 tion in the number and shape of the cusps is not due to pecu- 

 liarities of wearing. In the 3-pointed teeth two accessory cusps 

 are developed behind the principal one, while in teeth with four 

 points there is also a small accessory cusp in front of the prin- 

 cipal one. In one instance a first lower molar has two minute 

 points placed in front of the principal one, there being a 

 (purely supernumerary) cusp on the outer anterior border of 

 the tooth. In the males the teeth average (in linear dimen- 

 sions) about one-eighth larger than in the females; but the size 

 varies so much in individuals of the same sex that the teeth 

 are as large in some females as in some males. 



