ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



59 



Fig. 39. Sagittal sections of skin from the top of the head of Pacific walrus calves, show- 

 ing stages in the postnatal molt: (a) at 2 weeks after birth, with compact stratum 

 corneum (S), elevated club roots (C) of the second (natal) pelage, and quiescent, unpig- 

 mented hair bulbs (B); (b) at 1 month after birth, with loosening stratum corneum, club 

 roots of the natal pelage still in place, and hair bulbs becoming pigmented; (c) at 

 2 months after birth, with hair bulbs descendent and enlarged; and (d) at 2.5 months 

 after birth, with most of the stratum corneum shed, some natal hairs still in place, and 

 hairs of the third (postnatal) pelage heavilv pigmented, deeplv rooted, and growing. 

 (Photos by G. C. Kelley) 



pelage" and that the "whitish fetal coat" had been lost in the course of the walrus' 

 evolution. As I have shown in the foregoing account, the predicted whitish 

 lanugo has not yet been lost, though it is of rather short duration and is shed well 



