OVARY AND OVARIAN OVA IN CERTAIN MARINE FISHES. 157 



my paper in the ^ Journal of the Marine Biological Associa- 

 tion' that the ripe conger lives for about six months without 

 taking food, there can be no doubt that all the fat in the testis 

 is absorbed long before the milt is all shed. 



Summary and Conclusions. 



In fishes which have pelagic ova and an annual spawning 

 season, the formation of yolk in the developing ova to be shed 

 at a given spawning season commences some mouths after the 

 close of the preceding spawning season. The active develop- 

 ment of the annual crop of ova does not take much more than 

 six months. 



The formation of yolk always commences near the surface of 

 the cytoplasm and extends inwards. 



In those eggs which develop separate oil globules, a few of 

 these of small size are present long before the formation of 

 yolk commences. The eggs of the mackerel form an exception 

 to this statement. In immature specimens of sole, turbot, 

 brill, &c., examined during the spawning season, the largest 

 ova in the ovaries are found to contain scattered oil globules, 

 and these are also present in the largest transparent ova in 

 spent ovaries of these species. When the formation of yolk 

 takes place in such eggs the oil globules form a zone internal 

 to that of the yolk. 



The essential peculiarity of the spent ovary is the presence 

 in it of the ruptured follicles, from which the ripe eggs have 

 escaped. The follicular epithelium in these appears to dis- 

 integrate and dissolve. The cavity is obliterated by the con- 

 traction of the follicle, which forms a mass of cells and fibres, 

 and is finally absorbed soon after the commencement of the 

 formation of yolk in the eggs for the following season. 



In the spent ovary there are a number of eggs which have 

 not reached the ripe condition, which die, and are not dis- 

 charged from their follicles, but absorbed in situ. In the 

 fresh state they are visible as opaque amorphous masses. 



Similar opaque, masses are also seen in immature ovaries in 



