PLATE IX 



Skulls in ventral view. 

 Male. Fig. i. No. 653. First year group. 

 Male. Fig. 2. 1.1.4.15. Second year group. 

 Male. Fig. 3. S.S. 2. Third year group. 

 Male. Fig. 4. No. 679. Fourth year group. 

 Female. Fig. 5. No. 663. First year group. 

 Female. Fig. 6. B. 144. Second year group. 

 Female. Fig. 7. 325 rf. Third year group. 

 Female. Fig. 8. B. 145. Fourth year group. 



The relative sizes of the skulls are not exactly represented. For dimen- 

 sions see pp. 251 and 254. 



