GERM-CELL ORIGIN 



123 



Species 



Place of Origin, etc. 



Author 



Ambystoma 

 maculutiim 



Most germ cells somatic in origin 

 from germinal epithelium, al- 

 though a few may come from pri- 

 mordial germ cells of entodermal 

 origin 



McCosh. 1930. 

 J. Morphol. 50 



Triton, and 

 Ambystoma 

 mexicanum 



Germ cells differentiate from lateral 

 plate mesoderm 



Nieuwkoop. 1946. 

 Arch. Neerl. de zool. 7 



Chrysemys 

 marginata 

 (turtle) 



Primordial germ cells from ento- 

 derm; most of definitive germ cells 

 arise from peritoneal cells 



Dustin. 1910. 



Arch, biol., Paris. 25 



Sternotherus 



odoratus (turtle) 



Primordial cells segregate early from Risley. 1934. 



entoderm; later definitive cells de- J. Morphol. 56 

 rive from these and from peri- 

 toneal epithelium 



Callus (domesticus) 

 gallus (chick) 



Germ cells arise from primitive cells 

 in entoderm of proamnion area 

 and migrate by means of the 

 blood vessels to the site of the 

 developing gonad. Definitive germ 

 cells of sex cords and later semi- 

 niferous tubules derive from pri- 

 mordial germ cells 



Swift. 1914, 1916. 

 Am. J. Anat. 15, 20 



Gallus (domesticus) 

 gallus (chick) 



Primordial germ cells arise from en- 

 todermal cells 



Dantschakoff. 1931. 

 Zeit. f. Zellforsch., 

 mikr. Anat. 15 



Chick and albino Early primordial cells degenerate; Firket. 1920. 



rat definitive cells from peritoneal Anat. Rec. 18 



epithelium 



Didelphys 

 virginiana 

 (opossum) 



Germ cells arise from germinal epi- 

 thelium 



Nelsen and Swain. 



1942. 

 J. Morphol. 71 



Mus musculus Oogonia derived from primordial Kirkham. 1916. 



(mouse) germ cells; spermatogonia from Anat. Rec. 10 



epithelial cells of testis cords 



Mus musculus Primordial germ ceils of ovary arise 



(mouse) from germinal epithelium during 



development of the gonads. These 

 presumably give origin to the de- 

 finitive sex cells 



Fells domestica Primordial cells segregate early but 



(cat) do not give origin to definitive 



germ cells which derive from ger- 

 minal epithelium 



Brambell. 1927. 

 Proc. Roy. Soc. Lon- 

 don, s.B. 101 



de Winiwarter and 

 Sainmont. 1909. 

 Arch, biol., Paris. 24 



