OVARY AND OVARIAN OVA IN CERTAIN MARINE FISHES. 151 



In the eggs of" the conger and eel, as in those of the gurnard, 

 turbot, brill, &c., above described, the formation of oil globules 

 in the cytoplasm precedes that of the yolk proper. But the 

 deposition of fat occurs at a certain stage not merely in the 

 eggs but in the stroma or interovular tissue of the ovary, and 

 suggests that there is some important relation in the nutritive 

 processes between fat and proteinaceous vitelline substances. 

 Whether the fat is actually combined with other substances to 

 form nitrogenous compounds, or is merely used up separately 

 to supply the energy required by tbe body while the vitelline 

 constituents are being produced from other sources, is a phy- 

 siological question I am not prepared to discuss. Whatever 

 the function of the fat, there are three distinct periods in the 

 liistory of the ovary : (1) a stage in which the organ is very 

 small, and contains only protoplasmic ova destitute of deuto- 

 plasraic elements, and in which the stroma of the ovary is 

 small in quantity and destitute of fat-cells; (2) a stage in 

 which fat is largely deposited in the stroma in the form of fat- 

 cells, and the eggs are isolated from one another by this adi- 

 pose tissue, and in which the eggs themselves contain oil 

 globules ; (3) a stage in which the fat in the stroma is gradu- 

 ally absorbed, and yolk globules are developed in the eggs : at 

 the end of this stage a condition is reached in which the ovary 

 resembles in the structure of the stroma the earliest stage (1), 

 and consists almost entirely of eggs, now much larger and full 

 of yolk, crowded together. 



The first of the stages above defined is seen in the ovaries 

 of female conger which are 2 feet in length. The ovary in 

 such specimens is 3 to 7 ram. in width, and the breadth of the 

 lamellae, measured from the attached base to the free edge, 

 does not exceed '6 ram. These lamellae contain small protoplas- 

 mic eggs entirely without secondary deposits (fig. 31, PI. 4). The 

 greater number of these eggs are of nearly uniform size, and 

 these are the largest eggs present. Their diameter in my 

 preparations from one specimen of 2 feet in length is "05 mm. 

 There are a smaller number of smaller eggs, and at the surface 

 of the lamellae is seen the germinal epithelium, which in a 



