4 Transactions of the Society. 



The methods of (.'iijal and Da Fano, which depend upon silver 

 impregnation, do not give such clear and definite pictures of the 

 apparatus as those previously mentioned, and preparations made 

 by these methods were used^chiefly as controls. 



Although the mitochondria show quite well in Mann-Kopsch 

 preparations stained with acid fuchsin, they show more clearly with 

 riemming-without-acetic, or Zenker-without-acetic fixation and 

 iron haematoxylin staining. By these methods the mitochondria 

 stain a deep black. Tlie cytoplasm is of a pale bluish grey colour, 

 much darker in the youngest oocytes. The nucleoli are black, as 

 well as the mitochondria, while the Golgi elements in those cases 

 where they stain are black also. In slides untreated with turpentine 

 the yolk appears as deep brown coloured spheres. 



The Ovary of Patella. 



The ovary of Patella is situated on the ventral side of the 

 visceral mass. According to Davis and Fleure (7), " in very young 

 forms it is practically a pouch, the cavity of which is coelomic. 

 This cavity is lined by germinal epithelium, M'hich, with its under- 

 lying tissue, grows in as folds, some of which unite into trabecul?e, 

 thus converting the pouch into a mass of sex cells covering the 

 connective basis. As the gland grows in each season towards 

 maturity it pushes forward, sometimes as far as the level of the 



EXPLANATION OP PLATE I. 



Lettering. — C, connective-tissue basis of trabecular wall; CH., chondriome 

 granule (granules comprising the mitochondrial complex of the cell) ; GA., Golgi 

 apparatus; GE., individual Golgi element or batonette ; GE.1-GE.4, Golgi 

 elements during the various stages of yolk formation ; GP., fragments of ihe 

 Golgi elements broken off from the fully-formed yolk spheres ; M, mitochondria ; 

 N., nvicleus of &gg\ NC. nurse cell or yolk cell; NOT., nucleus of connective- 

 tissue cell of the trabecula ; NE., solid material extruded from the nucleus ; NL., 

 nucleolus of egg; NM., nuclear membrane of egg; NN., nucleus of nurse cell; 

 OC, oocyte ; OY., ovum; V., vitelline membrane; Y, yolk sphere; Ya-Yd., suc- 

 cessive stages in the development of a yolk sphere; YS., yolk sphere of nurse cell. 



Fig. 1. — Portion of the trabecula of the ovary, showing developing oocyte 

 (OC.) and nurse cells (NC). F.W.A. and iron haematoxylin. 



Fig. 2. — Young oocyte with Golgi apparatus (GA.) in concentrated condition. 

 De Fano and Jlann's metbyl-blue eosin. 



Fig. 3 — Similar young oocyte from a ^laun-Kopsch-Altmann preparation, 

 showing the Golgi apparatus after treatment with turpentine. 



Fig. 4. — Slightly older oocyte, with the Golgi elements (GE.) beginning to dis- 

 perse. Technique as fig. 3. 



Fig. 5. — Oocyte with the Golgi elements (GE.) spreading out in the cytoplasm. 

 ]\I.K. with turpentine. 



Fig. 6. — Young oocyte, showing the emission of solid nucleolar material (NE.). 

 ^lann-Kopsch-Altmann. 



Figs. 7, 8. — Young oocytes between the stages shown in figs. 4 and 5, illustrat- 

 ing the formation of yolk as the Golgi elements disperse. M.K.A. 



