The methods adopted in my investigations were
as follows, (1) the examination of the immature and
ripe ovaries in the living fish or in the fresh condition, without preparation, (2) the microscopical
examination of parts of the fresh ovaries and of the
intra-ovarian eggs at various stages, without preparation, in various media, (3) the study of stained and
mounted sections of the ovaries and eggs prepared in
the the usual way, (4) the determination in certain cases
of the general nature and quantity of the intra-ovarian
fluid present in ripening ovaries, (5) experimental observations on the physical properties of the
opaque and the transparent mature eggs, and on some
other points.
The species whose ovaries and eggs have been
investigated comprise the following :
A. With Dispersed Pelagic Eggs :
Grey Gurnard (Trigla gurnardus)
| Red Gurnard (Trigla cuculus)
| Lesser Weever (Trachinus vipera)
| Mackerel (Scomber scomber)
| Dragonet (Callionymus lyra)
| Cod (Gadus morrhua)
| Haddock (Gadus aeglefinus)
| Bib (Gadus luscus)
| Whiting (Gadus merlangus) | Saithe
(Gadus virens)
| Ling (Molva vulgaris)
| Fourbearded Rockling (Motella cimbria) | Tusk (Brosmius brosme) |
Halibut (Hippoglossus vulgaris)
|
Long Rough Dab (Hippoglossoides limandoides)
|
Turbot (Rhombus maximus)
|
Brill (Rhombus laevis)
|
Sail-fluke (Arnoglossus megastoma)
|
Plaice (PIeuronectes plati'ssa)
|
Lemon Dab (Pleuronectes microcephalus)
|
Witch (PIeuronectes cynoglossus)
|
Common Dab (Pleuronectes limanda)
|
Flounder (Pleuronectes flesus)
|
Sole (Solea vulgaris)
|
Solenette (Solea lutea)
|
Norwegian Topknot (Zeugopterwis norVegicus)|
Sprat (Clupea sprattus)
B. With Floating Eggs imbedded in Mucus :
Angler, or Monk Fish (Lophius piscatorius)
C. With Demersal Eggs:
Short-spined Cottus (Cottus scorpius)
Long-spined Cottus (Cottus bubalis)
Pogge (Agonus cataphractus)
Lumpsucker (Cyclopterus lumpus)
Diminutive Sucker (Liparis montagui)
Catfish (Anarrhichas lupus)
Lesser Sand Eel (Ammodytes tobianus)
Sparling (Osmerus eperlanus)
Herring (Clupea harengus)
The immature ovaries of the John Dory (Zeus father) and the common eel (Anguilla vulgaris) were also
examined. The eggs of the Angler are pelagic in the
sense that they float at the surface of the sea, but
they are not separate and dispersed like ordinary
pelagic eggs, being imbedded in a large quantity of
mucus forming a long band which floats them; the
eggs themselves are of the demersal type. „ The eggs
of the John Dory have not hitherto been described;
from a study of the features of the immature eggs they appear to be demersal. The ova of the eel and conger, according to the recent researches of Grassi,(29) are pelagic, as was previously surmised by Raffaele (64). Stained and mounted sections of the ovaries
and intra-ovarian eggs of the following species were prepared and examined : - Haddock, Whiting, Bib,
Grey Gurnard, Plaice, Lemon Sole, Flounder, Common
Dab, Witch, Sole, Solenette, Norwegian Topknot, Long
Rough Dab, John Dory, Viviparous blenny, Monk fish, arc.
Common Eel. The eggs and portions of the ovaries
of the following species were examined microscopically in the living or fresh condition in the ovarian
succus, and in various media : - Cod, Haddock,
Whiting, Ling, Saithe, Bib, Fourbearded Rockling,
Gurnard, Red Gurnard, Turbot, Brill, Halibut, Plaice,
Lemon Sole, Witch, Common Dab, Flounder, Sole, Solenette, Norwegian Topknot, John Dory, Lumpsucker, Catfish, Herring.
The quantity and general character of the ovarian fluid was determined in the cod, ling, haddock,
flounder, and plaice; by the courtesy of Professor
Rutherford a special determination was made in the
Physiological Department by Dr Milroy, with respect
to the composition of the ovarian fluid of the plaice.
Dr Milroy was also kind enough to investigate many
other points of interest bearing upon my work, which
are referred to later.
