THE DOCTRINE OF IMMORTALITY 



51 



Lepidosteus 



Lepidosleus 



\Periph. End, 



\Vil End. 



Fig. 24. — Diagrams to show the migration of sexual cells in four different verte- 

 brates. Arch, primitive intestine (archenteron) ; Int, intestine; Lat. Mes, lateral 

 mesoderm; Mes, mesothelium, or wall of the body cavity; Meson, embryonic kidney 

 (mesonephros) ; Myo, anlage of the muscle (myotome); Noto, primitive axis (noto- 

 chord); S.C, sexual cells in migration; W.D, renal, or Wolffian duct. — After Bennett 

 M. Allen. 



