PLATE 4 



EXPLANATION OF FIGURES 



21 and 22 Two stages representing -the enlargement of the invagination 

 cavity and the breaking up of the mitochondrial ring. 



23 The beginning of the elongation of the invagination cavity. 



24 The invagination cavity is elongating to form the outer tube (o.t.) of the 

 spermatozoon, the nucleus is changing in shape and the finger-form process 

 (/'. p.) is appearing. 



674 



