ROYAL 
JOURNAL 
OF THE 
MICROSCOPICAL SOCIETY. 
JUNE, 1922. 
TRANSACTIONS OF THE SOCIETY . 
V.— THE MORPHOLOGY AND PHYSIOLOGY OF THE 
NUCLEOLUS.* 
Part I. — The Nucleolus in the Germ-Cell Cycle 
of the Mollusc Limnsea stcignalis. 
By Reginald James Ludford, Ph.D., B.Sc.(LoncL), F.R.M.S., 
Dept, of Embryology and Histology, 
University College, London. 
(Bead April 19, 1922.) 
Three Plates. 
1. Introduction. CONTENTS. 
2. Previous Work. 
(1) “Solid” Extrusions from the Nucleus during Gametogenesis and 
Development. 
(2) The Nucleolus in Somatic Cells. 
(3) Nucleolar Extrusions in Somatic Cells. 
(4) Cytomyxis. 
(5) Experimental Researches on the Nucleolus. 
(6) Theories as to the Function of the Nucleolus. 
3. Preliminary Investigations with Fresh-water Molluscs. 
4. Ontogeny of Limnaea stagnalis. 
5. Technique. 
6. The Behaviour of the Golgi Apparatus and Mitochondria during Gameto- 
genesis and Embryogeny. 
7. Behaviour of the Nucleolus during Oogenesis. 
8. The Nucleolus during Spermatogenesis. 
9. The Nucleolus during Fertilization. 
10. The Nucleolus during early Segmentation Stage. 
11. The Nucleolus during Blastula and Gastrula Stages. 
12. The Nucleolus during Larval and Adult Stages. 
13. Discussion. 
(a) Number of Nucleoli during Gametogenesis and Segmentation. 
( b ) Size of the Nucleolus. 
(c) Interchange of Materials between Nucleus and Cytoplasm. 
(d) Biochemical Considerations. 
(e) Extrusions from the Nucleus into the Cytoplasm during Cell-Division. 
(/) The Nucleolus and Morphological Changes in the Chromosomes. 
14. General Conclusions. 15. Summary. 16. Bibliography. 
* Part of the materials used in this research was purchased by a Government 
Grant of the Royal Society, for which I express my thanks. 
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