4 Fishery Board for Scotland. 



applied to it. . . . In the ovary, especially before the eggs are quite mature, it 

 will be found that each large egg is contained in a pyriform pouch, which projects 

 into the cavity of the ovary, and which, in such specimens, may be easily separated 

 at its pedicle. In the early stages, gelatinous matter between the pouches is not 

 apparent. When the large, mature eggs escape from their follicles, they pass 

 into the gelatinous secretion, and the mass is extruded no doubt gradually. The 

 process of expulsion through the narrow oviduct would appear to be a matter of 

 difficulty, and the mode in which fertilisation takes place is also a little puzzling. 

 The males are much more numerous than the females, in the proportion of 100 to 

 26, and it is probable several males attend the female during oviposition." 



The number of eggs in such an ovary has been estimated by Fulton. He 

 calculated that, in two nearly mature ovaries, there were 1,345,848 and 1,312,587 

 eggs respectively. 



The Floating Spawn. 



[Fig. 1). 



The eggs of the Angler, after expulsion from the ovary, are found floating in 

 the sea enveloped in a ribbon-shaped band of mucus. Agassiz (1882) described 

 the appearaiice of this floating mass of spawn. Some of the bands were from 25 

 to 30 feet long, and from 2 to 3 feet broad. Thus probably the whole of the 

 eggs from a single ovary are enveloped in this mucoid sheet. Fulton concludes 

 that in such a case extrusion must take place with some rapidity, and that im- 

 pregnation of the ova is assured by the great excess of males. 



The published records of the occurrence of sheets of spawn are discussed later. 

 Hitherto, however, descriptions of sheets of spawn have been confined to examples 

 in which the embryos were already far advanced in development, and the following 

 observations, the result of an examination of a mass in which the eggs exhibited 

 no trace of embryos, are therefore given. 



The eggs are arranged in a single irregular layer through the mass, and the 

 gelatinous material forms a series of polygonal cells almost hexagonal in shape 

 but with rounded corners, in which the eggs lie. When the investing jelly-like 

 material is examined under the microscope, the walls of each cell in optical section 

 appear as if made up of a series of very fine concentric lamellae. 



Each cell contains an egg, and the eggs are therefore quite separate from each 

 other. The egg is only about half the diameter of the cell, and, surrounded by 

 fluid which fills the remainder of the cell and acts as a buffer, the egg is not deformed 

 by contact with the sides of the cell or with other eggs. Thus each egg is free within 

 its cell, and can be turned about with the point of a needle ; it floats with its con- 

 tained oil-globule uppermost, and if the gelatinous sheet be turned over, the eggs 

 revolve within the cells so that the oil-globules are again on top. 



If the eggs are freed from the gelatinous material, they float at the surface of 

 sea-water and appear like normal large pelagic eggs. 



The mucous band is of a light violet-gray colour, and when the embryos are 

 well developed in the eggs the dark pigment spots of the young Anglers, still in the 

 egg, give to the mass a somewhat blackish appearance. 



Agassiz' figure of the spawn is somewhat misleading. Either the embryos 

 have hatched out from the eggs and are now free within the cells, or if the embryos 

 have not hatched out from the egg, the investing membrane is absent from the 

 illustration. Cunningham's suggestion that the gelatinous substance arises by a 

 modification of the outer surface of the zona radiata was apparently based on 

 Agassiz' description. Fulton (1897) has already pointed out that this is not the case. 

 " It (the gelatinous substance) is situated not only outside the follicle, but outside 

 the ovigerous pouch ; that is to say, it lies in the cavity of the ovary, and it is, in 

 reality, formed as a secretion by the colunmar epithelium." 



Isolated Eggs of Lophius Piscatorius. 

 The extensive investigations mad,e by the Scottish Fishery Eesearch Vessel, 

 Goldseeker, and other research vessels, have shown that the pelagic eggs, and the 

 larval and post-larval stages of our common food-fishes, can be caught in large 

 numbers with special apparatus. Notwithstanding the many extensive voyages 

 of investigation which have been made in recent years by these specially equipped 



