54 ROBERT SOHARFF. 



piscatorius, Salmo salar, Anarrhichas lupus, 

 Conger vulgaris, Blennius pholis, Hippoglossoides 

 liraandoides. 



In several cases the investigation was carried out on fresh 

 ovaries ; others were only inspected in a preserved condition. 

 I cut sections of all of them. They were hardened in weak 

 chromic or in picrosulphuric acid. 



With regard to the result of my researches, I may mention 

 that there were two features which seemed to me of special 

 interest. Firstly, the development of the yolk, and secondly, 

 the origin of the egg-membranes and the follicle. I think I have 

 been successful in tracing the first, and also answered part of 

 the latter question. But the smallness of the objects presents 

 great difficulties, and the ova, after they pass a certain size, 

 become so opaque that their structure has to be studied entirely 

 from sections of hardened specimens. I propose to divide this 

 paper into five chapters, beginning with the nucleus and its 

 changes, and finishing up with a general account of the 

 development of the intra-ovarian egg. An abstract of this 

 paper was read before the Royal Society at their meeting in 

 the beginning of December last. It will be found in this 

 year's Proceedings of the Society. 



The various stages of the growing ovum have all, or nearly 

 all, been seen in the gurnard's egg ; but, in order to show that 

 they also occur in the other forms, where it was possible, 

 illustrations have been copied from sections of the different 

 species examined. 



I. The Nucleus and its Changes in the Smaller Ova. 



I found the smallest ova, measuring O'Oll mm. in diameter, 

 in the ovary of the Haddock. In these eggs the nucleus 

 occupies almost the whole of the interior (fig. 1). A very 

 narrow zone of protoplasm, which, as far as I could ascertain, 

 was not bounded by a membrane, surrounded the nucleus. 

 The wall-less ovum lies in the endothelial or connective tissue 



