PLATE 7 



All figures, except figure 77, from Cambarus virilis; figure 77 from Cambarus 



immunis 



EXPLANATIOX OF FIGURES 



55 Telophase, second spermatocyte division of a type B primary spermato* 

 cyte showing one chromatoid body at one pole. 



56 Spermatid type B', with one chromatoid body in the cytoplasm. 



57 to 60 Successive stages in the transformations of the spermatid to form 

 the spermatozoon; side views, drawn from smear preparations. 



61 Top view of a transforming spermatid. 



62 View of an oblique section of a transforming spermatid, showing the 

 centrosome spinning out its flagella-like strands, C. 



63 Top view of a transforming spermatid showing the same structure as that 

 shown in figure 62. 



64 Side view of a transforming spermatid previous to the formation of the 

 rayed arms. 



65 Side view of a transformed spermatid showing the rayed arms, Z, formed 

 along the flagella-like strands, C, developed from the centrosome. The vesicle, 

 V, is completely formed, and the nucleus, A'^, forms the head piece. 



66 Top view, showing all the structures mentioned under figure 65, except N, 

 which is hidden by the vesicle and the rayed arms. 



67 Mature spermatozoon with the arms, R, tightly packed around the nucleus. 



68 to 72 and 74 Uncoiling of the spermatozoon as observed in Ringer's solution 

 H2O, Na and K salts. Figures 69, 72 and 74 are top views; the others are side 

 views. 



73 Top view of an uncoiling spermatozoon, drawn from a stained preparation. 



75 Side view of an opened spermatozoon showing the vesicle, V, the radiating 

 arms, R, and the nucleus, N. 



76 Top view of an uncoiled spermatozoon. 



77 Eight-rayed type of spermatozoon, the fourth type found in Cambarus 

 immunis. 



642 



