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The Germ-Cells. 



Part I. Raja batis. 



By 



John Beard, D. Sc, 



University Lecturer in Comparative Embryology, Edinburgh. 



With plates 43 — 44 and 3 figures in text. 



Contents. 

 Preface. 



Introduction. 



Methods of Investigation. 

 I. The Grerm-Cells in an Embryo of 32 mm. 

 II. The Distribution of Germ-Cells in earlier Embryos. 



III. The Germ-Cells in Embryos of 10—12 mm. 



IV. The Germ-Cells in Embryos of 6 — 8 mm. 

 V. The Germ-Cells in an Embryo of 14 mm. 



VI. The Germ-Cells in Embryos of 21—22 mm. 

 VII. The Germ-Cells in an Embryo of 26 mm. 

 VIII. The earliest History of the Germ-Cells in Embryos. 

 IX. The Germ-Cells in the pre-embryonic Period. 

 X. The Germ-Cells in the earliest Period of Embryo-Eormation. 

 XI. General Survey of the History of the Germ-Cells. 

 XII. Dermoid Cysts and Teratomata. 



XIII. The Degeneration of certain Germ-Cells. 



XIV. Primary and secondary Germ-Cells. 



XV. Germ-Cells, Germ-Plasm, and Somatic Cells. 

 XVI. Germ-Cells and Embryo. 

 XVII. The so-called Germinal Epithelium. 

 XVIII. The morphological Continuity of Germ-Cells. 

 Literature cited. 

 Description of Plates. 



Preface. 



"Der Mensch", writes the learned and genial Carl Ernst von 

 Baer, "sieht sich ebenso nothwendig in der Mitte seines geistigen 

 Horizontes, wie in der Mitte seines mathematischen." 



