26 Fishery Board for Scotland. 



When the preserved follicle was cut open, the egg was found to have a 

 coarsely granular yellow core surrounded by a finely granular thick 

 rind. A female had ripe eggs free in the ovary, but no segmentation 

 of the ovum was made out. The stalks of the eggs are noteworthy : 

 some are very long (,v., Fig. 83), others are short. The stroma exhibits 

 a network of fine fibres, and of vessels large and small. One fish had 

 a small ovary which was shrunken and mottled with brown. 



April. — A fish had ripe eggs still in follicle. They measured 1"0 

 to 1"15 mm. in diameter and had a yellow oil globule measuring "37 

 and '4 mm, in diameter. The eggs were translucent. When free 

 from the follicle the}'' appear to imbibe fluid (juickly and swell up. 



Developing embryos were found in the ovaries during April, May, 

 and June. The eggs had become free from the follicle, and the}" filled 

 the ovary with a semi-fluid mass. The egg has a delicate investment ; 

 one coat only was made out. The embryos were found in various 

 stages from the "'disc" stage up to the embr3'o which was ready to 

 hatch (Figs. 64, 65, 70, 71). Larvae and post-larv£e were also found in 

 the ovaries (Figs. 69, 77, 78). The posterior end of the ovary was well 

 supplied with blood. Its wall was distended, and very thin, permit- 

 ting the ova and larvee to be seen from the outside. 



The eggs varied in shape : some were oval, others round. Some 

 oval eggs measured in the fresh condition, 1*4 x l"l (oil globule "4) ; 

 1'4 X ri (o.g. '4); 1-3 X r05 (o.g. "4) mm. A round egg con- 

 taining an embryo was 1'12 (o.g. '4) mm. in diameter. Preserved 

 ovaries had eggs containing embryos measuring as follows : — 

 1"5 X 1'12 ; I'd; 1'15 ; 105 mm. Among the small pregnant fishes 

 obtained in June two of the developing free ova measured while fresh 

 17 X 1*4 (o.g. '4), and 1*7 x ri5 mm. The oil globule was green. 

 After preservation some ova obtained from the same lot of fishes 

 measured 1-7 x 1-35 (o.g. -4); 1-55 x 1-3 (o.g. -4); 1-45 x 1-32 

 (o.g. -4); 1-4 X 1-35 (o.g. -42): 1-4 (o.g -4): 1-4 x 1-3 (o.g. '4) mm. 



When the eggs have escaped from the follicles, the latter become 

 very large ( /?., Figs. 80 and 86). They are well supplied with blood : a 

 glomerulus can sometimes be made out in the swollen end. The 

 ovarian lobes, ovl., thickly covered with these follicles, stick out 

 through the semi-fluid mass of ova (Fig. 59) The follicles are no 

 doubt concerned in the aeration of the embryos and lavvjB. In Fig. 80 

 two ripe eggs (e) are still in follicle. The young eggs are concen- 

 trated in groups on the large vessels of the ovarian tissue. 



A fresh egg containing an embryo was put into formaline and it 

 rapidly became opaque white. It was soon difficult to make out the 

 oil globule and embrj'o. This was due to the fact that the 

 perivitelline fluid coagulated. 



In preserved ovaries two kinds of eggs (with embryos) were found ; 

 one an opaque egg, and the other a small translucent egg. When 

 some of the opaque eggs, which were usually large, although some 

 were small, were dissected, a thick outer finely granular opaque rind 

 was found inside the zona. When the rind was removed the embryo 

 was seen in several of the eggs, although not in all. When it was 

 found it was semi-circular in shape, approximately at the stage 

 represented in Fig. 65. In one large egg the embrj'o was visible 

 from the outside. The small translucent egg may also show the 

 embryo half-way round the yolk. Sometimes the zona is clearly 

 crumpled, as if the small ovum had lost the contents of its perivitelline 



