increase in percentage in older seals. Thus, 

 the combined percentages for early and late 

 molt are: 



by month of collection and 



To test whether the diameter of the hair 

 stump is a clue to its age, the transverse 

 (= greatest) width of 507stumps was measured. 

 (Measurements were made on photoenlarge- 

 ments at lOOX.) The sample represents 10 

 adult, nonmolting females collected between 

 January and early October. The results are 

 shown in table 9. Stump width varies widely 

 and for no apparent reason. Width frequencies 

 tend to be bimodally distributed. See, for 

 example, those for a 5-year-old in July 

 (table 9). This observation parallels another, 

 namely, that guard hair shafts are mainly of 

 two sizes, larger and smaller, with few inter- 

 mediates. 



adult, nonmolting fur seal females-"- 

 by age of seal in years 



Width frequencies 



Mean 



width, 



microns 93 75 90 69 71 80 67 86 77 82 77.4 



No. of 



roots in 



sample 37 68 29 62 60 44 65 47 43 52 507 



-'■ Transverse (greatest) width of each root stump near surface of skin; 

 measured from tissue sectioned horizontally in paraffin, stained and mounted. 



18 



