88 



Part Til. — Sixteenth Annual Report 



IL_ON THE GROWTH AND MATURATION OF THE 

 OVARIAN EGGS OF TELEOSTEAN FISHES. By T. 

 Wemyss Fulton, M.D., F.R.S.E., Scientific Superintendent. 

 (Plates I.— III.) 



Exact knowledge concerning tlie mature eggs of the great majority of 

 marine osseous fishes is of comparatively recent date. The structure or 

 anatomical relations of the reproductive organs were early made the subject 

 of investigation by such authorities as Rathke, Cuvier and Valenciennes, 

 Vogt, Owen, Hyrtl, and Waldeyer ; and the eggs, embryology, and 

 development of several species were studied before 1866 by Rathke, 

 Von Baer, Rusconi, Vogt, Doyere, Joh. Miiller, LerebouUet, Strieker, 

 Steenstrup, Ransom, and others. Since the year named a large number 

 of investigations have been made by various naturalists, especially, 

 perhaps, in connection with embryology. Previous to the period 

 indicated, the researches on teleostean embryology were confined either 

 to fresh-water species or to one or two marine shore forms, in which the 

 eggs are carried by one of the parents until they hatch, namely the pipe- 

 fishes {Syngnathus) and the viviparous blenny (Zoarces viviparus), and 

 which, therefore, provided specimens at various stages of development. 

 The fresh-water species which formed the subject of study were principally 

 the perch, pike, carp, trout, salmon, cliub, river-bullhead, ruffe, and 

 sticklebacks. One reason why the early investigations were almost 

 entirely confined to fresh-water forms was no doubt the comparative 

 ease with which living eggs could be obtained, the relatively large size of 

 the eggs, and the convenience with which they could be preserved alive. 

 But there was another reason, inasmuch as previous to the time named 

 scarcely anything was known about the eggs or oviposition of marine 

 Teleosteans. It was not until the discoveries of Sars respecting the eggs 

 and spawning of the cod, haddock, and mackerel that the attention of 

 zoologists was specially directed to the importance of the subject. Since 

 that time, although researches have naturally continued to be made on 

 fresh-water forms, by far the greater number have concerned marine 

 species ; a circumstance also due to the establishment of marine 

 laboratories in various countries, which have provided facilities that did 

 not previously exist. 



In 1864 G. 0. Sars, in the course of an investigation into the cod 

 fisheries of the Loffoden Isles, discovered that the mature eggs of the 

 cod consisted of minute, perfectly transparent spheres, which floated 

 about separately in the surface waters of the sea. In the following year 

 he artificially fecundated the eggs of this fish and studied the development 

 of the embryo ; and he also found that the eggs of the haddock and of 

 the mackerel were buoyant like those of the cod, as well as the eggs of 

 some other species which he succeeded in hatching but not in identifying.* 

 In 1867 A. W. Malm incidentally studied the eggs of the flounder, which 

 were found to be buoyant.! In the following year Kupffer published an 



* '*Oni Vinterstorskens {Gadus morrhua) Forplanting og Uclvikling. " Forhand. i 

 Videiiskahs-Selsk. i Ghristiania, aar 1865, p. 237 (1866) ; ludberetninger til Departmentet 

 for det Indre, 1864-78, Ghristiania, 1879. (Translations of these reports, except the last, 

 are published in the Report of the U.S. Fish Commission for 1877.) 



t " Bidrag till Kiinnedom af Pleuronektoidernes utveckling och byggnad." Konigl, 

 Svenska Vetenskaps Akad. Handlinyar, p. 1. 1867. 



