30 NORTH SEA INVESTIGATIONS. 



examining the ripe and ripening ovaries, as Dr. Fulton has done to a 

 great extent in his investigation of the fecundity of fishes. In some 

 cases, although the number of ripe eggs present is considerable, there 

 are others in various degrees of development, so that spawning is 

 prolonged. This is the case in the gurnard, and in some lishes with 

 attached ova, such as Syngnathus acus, Anarrhichas lujms (the cat fish) 

 and others. In the plaice, according to my own experience, and Dr. 

 Fulton's observations, a large number of ripe ova are shed at once, and 

 the season's crop is soon exhausted. There is no prolonged production 

 of young ova to succeed those ilrst shed. The lish being of a high 

 degree of fecundity, and having all its eggs nearly ripe at once, the 

 distension of the body by the ripe ovaries is very great. In accordance 

 with this state of things the testes are rather large, very much larger 

 than in the sole, and spent fish appear early in the spawning season. 

 The spawning process being thus completely and abruptly terminated, 

 the ovary reverts to a resting condition. At Plymouth I found a spent 

 specimen as early as January 28th, at Grimsby the first I recognised 

 was obtained on February 27th. The conclusion that the ovary does 

 revert to its original condition, based on the evidence given in my paper 

 on the ovaries of fishes, vol. iii., p. 154, has been confirmed by my 

 observations this season at Grimsby. It has been shown in former 

 papers by ]\Ir. Holt and myself, that in the spent ovary the chief 

 peculiarity is not the appearance of empty follicles from which ripe eggs 

 have escaped, but the presence of partially yolked eggs, which are found 

 to be afterwards absorbed. But the opaque granular masses to which I 

 have so often referred above, had not attracted my notice very much 

 before the present season. They are easily overlooked, not because 

 there is any difficulty in seeing them, but because they are so indefinite 

 in shape, and do not appear at first to have any important significance. 

 The history of the ovary could be worked out with more certainty if we 

 were able to examine specimens in captivity, the date of whose 

 spawning was known from actual observation. I have in a former 

 paper described a few such specimens, but they were not killed until 

 several months after spawning. 



I have not yet made a thorough examination of shotten herring, but 

 the few notes I have made tend to show that in the spent ovary the ova 

 are all quite yolkless and transparent, as in the immature ovary. A 

 newly-spent herring can be recognised from the llaccid and congested 

 condition of the ovary, but it is extremely probable that this condition 

 soon passes away. 



The haddock presents a condition similar to that of the plaice, that is 

 to say the spawning of an individual fish is soon over, the development 

 of the eggs being nearly simultaneous. On April 20th I examined 



