112 J. T. CUNNINGHAM. 



globules. The earliest stages seen were nearly transparent, 

 with minute globules at the periphery, and also minute 

 globules not much more opaque around the nucleus. I con- 

 cluded that the latter consisted of oil, and that in the mackerel 

 the deposition of oily substance and yolk commences in these 

 different regions of the egg simultaneously, and does not take 

 place in any eggs until some time after the previous spawning 

 season. In the eggs of the sole, I have not observed at any 

 stage the marked contrast in the fresh condition between the 

 darker and lighter zones which is seen in the eggs of the 

 gurnard and other species. In immature and spent specimens 

 a considerable proportion of the transparent young eggs contain 

 numerous scattered globules which are certainly oil globules. 

 They have a yellowish colour, and most of them are situated 

 near the periphery of the egg, forming a somewhat well- 

 marked layer. They can be seen even in the earliest stages in 

 prepared sections, but are much more conspicuous in the fresh 

 condition. 



The yolk proper begins to be developed after the spawning 

 season. In a specimen examined at Lowestoft, on September 

 20th, it had made considerable progress. It begins as usual at 

 the periphery of the egg outside the oil globules, and the latter 

 in portions of the ovary examined in the fresh state remain in 

 all stages visible through the yolk, and are conspicuous on 

 account of their somewhat large size, refringent character, and 

 yellowish colour. Fig. 13, PI. 2, shows the condition of the 

 most advanced eggs, as seen in prepared sections, in the ovary 

 of the specimen mentioned above, which was 16 inches long, 

 and was obtained in the market. The external portion of the 

 ovum contains yolk in the form of minute granules ; on the 

 inner side of the zone of yolk are the oil globules in groups 

 projecting into the protoplasmic zone, which is rather deeply 

 stained. 



In the nearly ripe egg of the sole as seen in sections pre- 

 pared from an ovary which was in process of spawning, oil 

 globules are not easy to distinguish. In the figure of such an 

 egg which I have given in my Treatise on the Sole, they have 



