254 Part HI. — Ninth Annual Report 
there were a large number of ova much more minute (0*8 to 0*9 mm.) 
scattered in the interstices. On careful examination I found a large fully 
mature ovum (the only one present), much more pellucid than the others, 
6'1 mm. in diameter, and weighing exactly 1'5 grains. I found that it took 
eleven of the ova, 2'1 to 2*5 mm. in diameter, to weigh this, and there 
were none intermediate iu size. I considered it a good example of what 
occurs in the development of the eggs in many fishes — a more or less 
gradual growth up to a certain point, and then a sudden expansion. The 
medium-sized ova had apparently begun to undergo this process prepara- 
tory to extrusion. There were a few (but very few) intermediate in size 
between the latter and the more minute ova, which no doubt served for a 
second crop. Sixty grains were weighed and counted ; they contained 
431 large ova, and 320 of the very minute ones ; so that the total number 
present in the ovaries would be — large, 14,388; small, 10,682 = 25,070. 
GASTEROSTEID^. 
Fifteen-Spined Stickleback (Gasterosteus spinachia). 
Two specimens caught at Dunbar in March gave the following results: — 
Length of 
Fish 
(in inches). 
Weight 
of 
Fish. 
Weight of 
Ovaries 
(in grains.) 
Weight of 
part taken 
(in grains). 
Number of 
Ova 
counted. 
Total 
Number 
of Ova 
in Ovaries. 
1 
210 
29 
« { 
Large, 121 
Small (?) 600 
585 
(?) 2900 
2 
en 
239 
20 
^ { 
Large, 128 
Small (?) 800 
640 
(?) 4000 
The bulk of the ovaries was composed of relatively large clear eggs, 
almost but not quite uniform in size (1*4 mm. to 1*3 mm.). Besides 
these, and between them, there was a great number of very small ova, 
from 0*7 mm., very difficult to enumerate. 
GADID^. 
Cod (Gadus morrhua.) 
Three specimens were examined — one caught on March 13, east of May 
Island ; one on March 24, also east of May Island ; and the third on May 
6, 100 miles east of May Island. The particulars are as follows :-- 
Length of 
Fish 
(in inches). 
Weight 
of 
Fish. 
Weight of 
Ovaries 
(in grains). 
Weight of 
part taken 
(in grains). 
Number of 
Ova 
counted. 
Total 
Number 
of Ova 
in Ovaries. 
1 
23 lb. 
32,409 
60 
7350 
3,970,102 
2 
38 
m „ 
33,006 
45 
9068 
6,652,390 
3 
35 
16 „ 
12,687 
30 
7008 
2,963,683 
In all these fish the roe was quite matured, and contained large clear 
ova, 1*2 to 1*4 mm. in diameter; in the first specimen some of the eggs 
had almost certainly been already expelled. The opaque ova ranged from 
0*8 to 0*5 mm. It will be noticed that in 30 grains of No. 3 there were 
almost as many ova as in 60 grains of No. 1. The weighing and enumera- 
tion were done with the greatest care. 
