ECOLOGY AND BIOLOGY OF THE PACIFIC WALRUS 



77 



Fetus, 300 mm, 5 October (serially sectioned). — Primary follicle formula 

 . 2-3 1 1-2-3-4 



^2:3 ^TP-TST"^-^'^'^- 



Unconsolidated dental laminae were present in the loci of i^ and i^ but were not 

 sufficiently organized to be classed as follicles. There was no dental lamina in the 

 locus of m^. Whereas the follicles of i2, pi, and m^ were incompletely organized 

 and lacked any trace of calcified tissue, each of the other primary follicles was 

 well organized and contained a calcified tooth. The diastema between cj and p2 

 was closed, as it was in all older specimens. The secondary dentition was 

 represented by follicles of 



I ^-^-3 c_L ^ 1-2-3-4 



1 2-3-4 



and primordia of M -j-. 



