114 J. T. CUNNINGHAM. 



in the fresh state, the most conspicuous characteristic is seen 

 to consist in a variable number of opaque, granular bodies of 

 irregular shape and structure. Investigation has proved that 

 these are eggs which have not fully matured, which have died 

 in situ, and which are not discharged from the ovary by the 

 bursting of their follicles, but are removed by absorption. In 

 the fresh material, when a number of fish are examined from 

 time to time, various stages in the disintegration of these eggs 

 are seen, from the condition in which the original structure is 

 but slightly altered, and which can only be distinguished from 

 that of the healthy eggs by the great opacity, to a condition in 

 which nothing is left but a small mass of opaque granules. 

 The appearance of two such dead yolked eggs as seen in the 

 spent ovary of a sole is shown in fig. 16. 



The presence of dead aborted eggs is not, however, the most 

 essential characteristic of ovaries which are spent. Such eggs 

 occur, as will be explained below, in other stages of the ovary. 

 Aborted eggs are absorbed in situ, but healthy ripe eggs 

 escape from the ovary by the bursting of their follicles, and 

 only ripe eggs escape in this way. The essential characteristic 

 of spent ovaries is, therefore, the presence of empty collapsed 

 follicles from which the eggs have escaped. So far as my 

 observations go, these empty follicles are not to be detected by 

 microscopic examination of fresh material ; in this all condi- 

 tions and stages of the eggs are easily seen, but the condition 

 of any part belonging to the connective tissue of the ovary is 

 very difficult to distinguish. In mounted sections, however, 

 the history of the follicle, after the escape of the egg, can be 

 studied with some success. 



In the fish ovary the follicle, after the escape of the matured 

 egg, passes through changes similar to those which are known 

 to occur in the so-called corpora lutea of the mammalian 

 ovary. In the fish ovary the] degenerating follicle is always 

 found in connection with the superficial membrane of the 

 germinal lamellse. When the egg escapes, the interior of the 

 follicle opens on to the surface of the ovarian lamella, and 

 the wall of the follicle is thus restored to the condition from 



