B¥ H. LEIOHTON KESTEVEN. 141 



which enters into yolk-formation. Clii'omatin-constituents, how- 

 ever, must be derived from without in tlie earliest stages. 



LITERATURE. 



1. (liOLDSCHMiDT — ■" Dev Clironiidialapparat lehliaft funetionierender (le- 



webszellen." Zool. Jahrb., xxi., 190."). 



2. Henneguv — "Le corps vitellin de Balhiaiii dans Wvni des Vertebre.s." 



Journ. Anat. Physiol., xxix., 1898. 



3. Kesteven — A new Endopaiasitic Copepod : M(>rpholo!j;y and Develop- 



ment. Proc. Linn. Soc. N. S. Wales, 1912, xxxvii.U918). 



4. MacCallum — "Contribution to tlie Morphology and Physiolooy of the 



Cell.'" Trans. Canadian Inst., i., 1891. 



5. McUiLL — "The Behaviour of the Nucleoli durino- Oogenesis of the 



Dragonti3' with special reference to Synapsis. " Zool. Jahrb., xxii. 

 1906. 



6. Montgomery — "Comparative cj^tological Studies, witii special regard 



to the Morphology of the Nucleolus." Journ. Morphoh, xv., 1899. 



7. Will — "Ueber die Entstehung des Dotters und der Epithelzellen bei 



den Amphibien und Insecten." Zool. Anz., vii., 1884. 



EXPLANATION OF PLATE III. 



Explanatory letters, — K., kar3'osomes — Nu'., the new nucleus in process 

 of formation — Nu"., the new nucleus nearlj'- formed — Nu. memb'., the 

 nuclear membrane of the old nucleus — Nu. memb"., the juielear membrane 

 of the new nucleus. 



Fig. 1. — The ultimate oogonium when first detached from the wall of the 



ovary. 

 Figs.2, 3, 4, 5. — Stages in the growth of the ultimate oiigonium. ,r^'-";: 



Figs. 6, 7. — Stages in the formation of the new nucleus. 

 Figs. 8, 9. — Sections of mature primary oueytes. iO">:,^!, ''i^J /.>'. K 



