OVARIES IN TELEOSTEAN AND ELASMOBRANCH FISHES. 161 



Observations on Ovarian Ova and Follicles in 

 Certain Teleostean and Elasmobranch Fishes. 



By 



William Wallace, U,Sc. 



With Plates 15-17. 



Introduction. 



The ovaries of certain species of Teleostean and Elasmo- 

 branch fishes were examined with particular reference to the 

 following points : 



(1) Post-embryonic origin of ova and follicular epithelium. 



(2) Yolk nuclei and their significance. 



(3) Egg-membranes and follicular epithelium. 



(4) Histology of egg-absorption. 



(5) Structural changes in ruptured follicles. 



Before proceeding to consider these points in order, I shall 

 give — (ft) a brief general description of the peculiar ovary of 

 Zoarces, based mainly on Stuhlmann's paper (1887) ; [b) 

 some data bearing on the rate of growth and comparative 

 fecundity of this species. 



(ft) Ovary of Zoarces. 



Our knowledge of the anatomy, histology^ and physiology 

 of the ovary of Zoarces is due chiefly to Forchammer 

 (1819), Rathke (1824 and 1833), and Stulilmann (1887). 



VOL. 47, PART 2. — NEW SERIES. L 



