384 TRANSACTIONS AND PROCEEDINGS OF [Sess. lvi. 



The nucleolus (3) is differentiated into an outer zone and 

 an inner zone. The outer zone is less deeply stained, and on 

 careful examination is found to be made up of a circle of 

 peripheral endonucleoli,* which are slightly elongated radi- 

 ally. The inner zone of the nucleolus is very darkly stained, 

 and shows a number of large and irregularly disposed endo- 

 nucleoli (4). 



Fig. 46 is very similar to the figure preceding it, but in 

 addition it shows a paranucleolus (jJ. n.) in the upper 

 nucleus ; the septum of the nucleus thinner in the 

 middle, and wavy, still unbroken, however, and separating 

 therefore the peripheral chromatin-granules ; and only 

 one large central endonucleolus in each nucleolus, and a 

 finely granular area in the upper nucleolus. 



For a full account of the literature on nuclei, I must refer 

 the reader to two excellent papers by Courchet and v. 

 Bambeke. Courchet t has specially referred to the early 

 literature on the endonucleoli, and has cjiven a short resumS 

 of papers by Flemming, Leydig, Hessling, Lacaze-Duthiers, 

 O. Hertwig, Schron, J. M. Macfarlaue, and Frommann. 

 Von Bambeke I has treated very systematically the various 

 nomenclature introduced by the different masters in cell- 

 study, and has also devoted special attention to the endo- 

 nucleoli, giving the views of Flemming, Frommann, Leydig, 

 Carnoy, van Beneden, and liimself. 



Fig. 47 represents the nucleolus of a micropylar prim- 

 ordial cell after the formation of a paranucleolus. The 

 remarkable fact is a radial striation (r. /.) of the nucleolar 

 chromatin-matter, and although the striation is by no means 

 very distinct, I believe this figure Lo fill a gap which exists 

 in figs. 45 and 4G, as we shall see afterwards. 



In how far can we corroljorate these observations in 

 MyoHuruH : — 



The resting nucleolus of the sporocyte, or embryo-sac-cell 

 (figs. 9'', 11, v.)'', 1.'^^ 14) dis])lays a large central unstained 



* Various terms have lioen used and are still in use i-eferriug to tlio unstained 

 areas in the nucleoli, such as "the granule of Schriin," or " nucleololus," or 

 " nucleolo-nucleus," or "vacuoles," and I ])ro])ose therefore to use the term 

 "endonucleolus," which was suggested to Dr Macfarlaue by Professor Ruthcr- 

 fonl ten years ago. 



+ Lucien Courchet, Du Noyau, Paris, 1884. 



+ Von Bambeke, Stru(;turc du Noyau Cellulairc a I'etat de Repos, 

 Oand, 1885. 



