OVARY AND OVARIAN OVA IN OEltTAIN MARINE FISHES. 107 



It is improbable that the great opacity of the inner zone in 

 tlie ova seen in the fresh condition, could be due to the some- 

 what large and not very numerous oil globules which are most 

 conspicuous in the sections, and in fact the appearance in the 

 fresh condition indicates very numerous minute globules. 

 Fig. 7 represents the appearance of an egg in the stage here 

 described. The preparation from which it was taken was 

 made from portion of an ovary of Trigla gurnard us, ob- 

 tained in the market on April 26th. The material was pre- 

 served vvith a mixture of picro-sulphuric acid and spirit, and 

 the sections were stained with Delafield's haematoxylin. Sec- 

 tions from material similarly treated, preserved at sea imme- 

 diately after the death of the fish on July 22nd, contain eggs 

 in a similar stage, and show in them the same structure, but 

 for some reason or other the outline of such eggs in these 

 sections is distorted, and I have therefore preferred to draw 

 from the others. In the sections from the fresh material the 

 inner zone of protoplasm shows more distinctly the minute 

 cavities which I believe to be the smallest oil globules. In 

 sections from some of the same material preserved in chromic 

 acid ^ per cent., the structure at this stage is not so well 

 shown. The yolk and oil globules are less distinct, and there 

 is a broader internal zone of more homogeneous protoplasm 

 with a rather distinct boundary just within the zone of larger 

 oil globules. 



In the later stages, i.e. in larger eggs as seen in the sec- 

 tions, the zone of yolk globules has increased in thickness and 

 extends to the zone of oil globules. Fig. 8 shows the appear- 

 ance of a section of an egg '37 mm. in diameter, preserved 

 immediately after death in picro-sulphuric acid and spirit. 

 The yolk globules themselves are now larger, and under a 

 high power are seen to be solid, i. e. coagulated spheres, often 

 with granules in their interior; usually some slight space is 

 seen between the outline of the globule and that of the vacuole 

 which it occupies. The yolk globules are stained a light 

 yellow by the picric acid, but do not usually take much colour 

 from the staining reagents used. The outer oil globules are 



