Fig. 17. Diagrammatic cross sec- 

 tions of the principal piece of the 

 sperm tail in several different species, 

 showing the variations in the shape 

 and thickness of the fibrous sheath and 

 in the size and position of the outer 

 dense fibers. A. Bandicoot (from Cle- 

 land and Rothschild, 1959). B. Opos- 

 sum C. Rat. D. Guinea pig. E. Bat. 



167 



