342 Payers from the Department of Marine Biology. 



von Berenberg-Gossler; and sympathetic ganglia in the loggerhead 

 turtle, Jordan) ; and to their apparent primary (urodeles) or secondary 

 (anurans and other vertebrates) derivation from the splanchnic layer 

 of the lateral mesoderm — are incidental to their original location with 

 respect to the embryonic area and the vascularizing mesoblast of the 

 blastoderm, and to their amoeboid capacity. Since the primordial 

 germ-cells are genetically directly related to neither of the secondary 

 germ-layers, their origin in either (entoderm or mesoderm) has no 

 fundamental significance. Since they are capable of amoeboid activity, 

 and may become included in blood-vessels, they may migrate any- 

 where, and so occur in any location, from where they may subsequently 

 migrate again to the more direct germinal path, or perhaps disintegrate. 

 The fact of fundamental significance with respect to the primordial 

 germ-cells is their original extra-regional distribution and their direct 

 genetic independence of the soma-cells. 



BIBLIOGRAPHY. 



Allen, Bennet M. 1904. The embryonic development of the ov^ary and testis of the 



Mammalia. Amer. Jour. Anat., vol. iii, p. 189. 



. 1906. The origin of the sex-cells of Chrysemys. Anat. Anz., Bd. 29. 



. 1907a. A statistical study of the sex-cells of Chrysemys marginala. Anat. Anz., 



Bd. 30, p. 391. 

 . 19076. An important period in the history of the sex-cells of Rana pipiens. 



Anat. Anz., Bd. 31, p. 339. 

 . 1911. The origin of the sex-cells of Amia and Lepidosteus. Jour. Morph., vol. 22, 



Beard, J. 1900. The morphological continuity of the germ-cells in Raja batis. Anat. 



Anz., Bd. 18. 



. 1904. The germ-cells. Part I. Jour. Anat. and Physiol., vol. 38. 



V. Berenberg-Gossler, H. 1912. Die Urgeschlechtszellen des Hiihnerembryos am 3. und 



4. Bebmtungstage, mit besonderer Beriichsichtung der Kern- und Plasma- 



strukturen. Archiv f. mikr. Anat. Abteilung ii, Bd. 81, s. 24. 

 . 1914. Ueber Herkunft und Wesen der sogenannten primaren Urgeschlechtszellen 



der Amnioten. Anat. Anz., Bd. 47, s. 241. 

 Boveri, Th. 1904. Ergebnisse uber die Konstitution des chromatischen Substanz dea 



Zellkems. Fischer, Jena. 

 BucHNER, P. 1910. Die Schicksale des Keimplasmas der Sagitten in Reifung, Befruch- 



tung, Keimbahn, Ovogenese, und Spermatogenese. Festschr. f. R. Hertwig. 

 Dantschakoff, V. 1908. Entwicklung des Blutes bei den Vogeln. Anat. Hefte, Bd. 37. 

 d'Hollander, F. 1904. Recherches sur I'oogenese et le noyau vitellin de Balbiani chez 



les oiseaux. Arch d'Anat. micr., T. 7. 

 DusTiN, A. P. 1907. Recherches sur I'origine des gonocytes chez les Amphibiens. Arch. 



deBiol., T. 23, p. 411. 

 . 1910. L'origine et revolution des gonocytes chez les Reptiles. Arch, de Biol., 



T. 25, p. 495. 

 Eigenmann, C. H. 1892. On the precocious segregation of the sex-cells in Cymaiogaster 



aggregatus Gibbons. Jour. Morph., vol. 5, p. 481. 

 . 1897. Sex-differentiation in the viviparous teleost Cymaiogaster. Arch. f. 



Entw.-Mech., Bd. 4, s. 125. 

 Felix, W. 1906. Die Entwicklung der Keimdriisen und ihrer Ausfiihrungsgange. 



Handb. d. Entw. von O. Hertwig. 



. 1911. Keibel and Mall's Human Embryology, vol. ii, chap, xix, p. 882. 



FiCK, R. 1906. Vererbungsfrage, Reduktions- und Chromosomenhypothesen, Bastard- 



regehi. Ergebn. d. Anat. u. Entw., Bd. 16. 



