280 Scientific Proceedings, Royal Duhlin Society. 



3. Ill silver preparations dark zones are found around the Golgi elements. 

 These probably represent a product of its activity. 



4. Long and sometimes branched Holmgreir canals were found in the 

 neurones. They were separate and distinct from the Golgi elements. There 

 was some evidence for considering them processes of the subcapsular cells, but 

 not sufficient to come to any definite conclusion. 



5. From the position occupied by the apparatus in nei-ve and germ cell, 

 from its similarity of micro-chemical reaction in both, and from embryological 

 evidence, it is Ijelieved that the nebenkern batonettes of the invertebrate 

 germ-cells are homologous to the Golgi network of the mammalian neurone. 



Bibliography. 



1. BoLLES Lee. — The Microtomist'sNVade Mecum. Gatenby, 1922. 



2. Brambell, p. W. Rogers. — The Activity of the Golgi Apparatus in the 



Neurones of Helix aspersa. Jour. Physiol., Aug., 1923. 



3. Gatenby, J. Bronte. — The Cytoplasmic Inclusions of the Germ-cells. 



Part, V. 



The Gametogenesis and Early Development of Limnaea 



stagnalis (L), with special Reference to the Golgi Apparatus and the 

 Mitochondria. Quart. Jour. Micr. Sc, Vol. 63, Part IV. 



4. The Gametogenesis of Saccocirrus. Quart. Jour. Micr. 



Sc, Vol. 66, 1922. 



5. Golgi, CiUviiLLO. — Interno alia structura delle cellule nervose. Boll. Soc. 



Med. Chr. di Pavia, 1898. 



6. HiRSCHLER, J. — Ueber den Golgischen Apparat embryonaler Zellen. Arch. 



fur Mikr. Anat. Bd. 91, Abt. 1. 



Description of Plate XVII. 



Key to lettering : — Golgi apparatus in extra-centric position (G.), and in 

 subsequent stages of breaking up (Gj and G,), Golgi Rods (G.R.), Ghosts of 

 Golgi Rods (G.G.R.), Argentophil zone surrounding Golgi elements (A.Z.), 

 Mitochondria (M.), Holmgren's canals (H.C.), Granules (Lecithin?) (A.), 

 Nucleus (N.), Plasmasome (P.), Region of Axon hillock (H.). 



These drawings were made with the help of a camera lucida. 

 Fig. 



1. Small neurone with Golgi apparatus in perinuclear extra-centric position. 



Da Fano preparation. X 4000. 



2. Small neurone with Golgi apparatus beginning to spread. Da Fano 



preparation. X 4000. 



3. Fuither stage in spreading out of Golgi apparatus. Da Fano preparation. 



X 4000. 



4. Medium-sized neurone with (lolgi apparatus spread around nucleus. Da 



Fano preparation. X 2500. 



5. Large neurone. Golgi rods small and scarce in region of Axon hillock (H.). 



In this and the preceding figui'e the argentophil zones around the rods 

 are shown. Da Fano preparation. X 600. 



6. Large neurone showing lecithin granules (A) and ghosts (G.G.R.) where 



the Golgi rods have been dissolved away. Champy-iron-haematoxylin 

 preparation. X 1300. 



7. Medium-sized neurone showing lecithin granules. From living cell. 



8. Portion of large neurone showing Holmgren "s canals in cytoplasm. X 1300. 



