498 
DK. W. H. RANSOM ON THE OVUM OF OSSEOUS FISHES. 
The colloid matrix not granular, the germinal spots variously tailed, dark- 
bordered and vacuolating. 
Fig. 19. Germinal spots, more highly magnified, seen in a 1| per cent, solution of 
chloride of sodium, variously tailed and vacuolating. 
Fig. 20 (Plate XVI.). Germinal spots in various stages of fusion and solution, in a 5 per 
cent, solution of chloride of sodium. 
Fig. 21 (Plate XVI.). A macerated yelk-sac: — a, the changed homogeneous-looking ex- 
tensile outer layer ; b , the dotted yelk-sac not changed. X 250 (drawn with a 
camera). 
Fig. 22. Appearance presented by the extensile outer layer under a magnifying power 
of X 3000 diameters ; the dots dark (diagrammatic). 
Fig. 23. Aspect of the same when the focus is so arranged that the dots are light. 
X 3000 (diagrammatic). 
PLATE XVI. 
Fig. 24. Egg of the Trout, showing the cup of the micropyle under a lens. 
Fig. 25. The micropyle of the egg of the Pike seen in f-face with reflected and trans- 
mitted light: — a , the trumpet-shaped tube. X 190. 
The figures 26 to 33 inclusive refer to the ova of Perch. 
Fig. 26. A diagram explanatory of the arrangement of the outer ends of the “ tubes ” in 
the outer layer of the yelk-sac of the ovum of the Perch : — a, the funnel-shaped 
mouths ; b, the “ tubes ; ” c, radiating curved furrows and folds of the surface. 
Fig. 27. Shows the arrangement of the “tubes” in a vertical section where two eggs 
meet. In the figure the “ tubes ” are stretched and broken, and their spiral 
twist destroyed. xl90. 
Fig. 28. Small fragments of the “ tubes ” more highly magnified to show the double 
contour of the walls. X 500. 
Fig. 29. The inner branched ends of the “ tubes:” — a, the outer laminated surface of the 
dotted yelk-sac ; b, a detached “ tube.” 
Fig. 30. The inner branched ends of the “ tubes ” seen from the inner surface of the 
yelk-sac through its substance, showing their relation to the finer dottings. 
Fig. 31. The outer ends of the tubes seen full face, showing their regular arrangement 
in the clear matrix, and the aspect of the funnel-shaped ends. xl90. 
Fig. 32. The dotted yelk-sac, showing its laminated structure at a fissure. X500. 
(The drawing exaggerates somewhat.) 
Fig. 33. The dotted yelk-sac, showing a cut edge. X 500 (also somewhat exaggerated). 
