When the fish spawns, some mature 
eggs remain in the ovary and are reabsorbed, 
These residual eggs can be recognized by 
their shriveled appearance and dark colora- 
tion. In late stages of reabsorption they are 
often arranged in dark clumps like a string 
of misshapen beads imbedded in the follicular 
tissue. 
6200 
6150 
200 
i In this paper the ovaries will be 
i designated immature, early maturing, late 
maturing, and mature according to whether 
they are found with primitive eggs only, with 
opaque eggs before the appearance of oil 
globules, with opaque eggs with oil globules, 
or with large eggs which are translucent, 
150 
ESTABLISHMENT OF 
SAMPLING PROCEDURES 
NUMBER OF EGGS IN SAMPLE 
| 
ir 
ir 
100 | 
1 
| 
Determining the most efficient method of 
50 measuring diameters 
Although basically spherical, the eggs 
are distorted by pressure from other eggs in 
the ovary. This posed a problem concerning 
the most efficient method of measuring an 
EGG DIAMETER(MM) egg. One alternative was to measure the 
maximum and minimum diameters and aver- 
Figure 1, --Frequency distribution of egg dia- age them; another was to measure the dia- 
meters from the ripest ovary from meter which occurred, by chance, parallel 
the central equatorial Pacific to guide lines ruled in the Sedgewick-Rafter 
(no. 57). counting chamber used as a receptacle during 
the measuring. Both of these techniques 
provide estimates of the average diameter, but a greater variance would be expected with the 
latter that would make it less efficient. To compare the variances, 50 mature eggs were 
measured from an ovary (no. 24) by both procedures, The results of the measurements are 
recorded in units of 7.5 microns in table l, 
If the relative efficiency of the two methods is judged by their variances, 37.59 and 
88,35 respectively for the averages of the maximum and minimum diameters and for the random 
diameters, obtaining the average diameter is 2.4 times as efficient as measuring the random 
diameter, In terms of work involved, however, the statistically more efficient method would 
require two measurements, each of which would be more time consuming than the one measure- 
ment of the random diameter. Still more work would be required to calculate the average. 
Measuring the random diameters was, therefore, the method selected. This diameter may be 
defined as the distance between two parallel lines tangent to the egg and normal to the rulings 
on the counting chamber. 
Distribution of eggs within an ovary 
The distribution of the most mature group of eggs within an ovary was studied as a 
further preliminary step in establishing a procedure for sampling each ovary. Cross-sections 
were taken from the anterior, middle, and posterior parts of the right member of the largest and 
seemingly most mature pair of ovaries in the collection at that time (no. 63). The sections were 
labelled J], 2, and 3 respectively, From each section six samples, two near the periphery 
(labelled Ay and Az), two near the center (labelled Cc) and C2), and two from between these 
positions (labelled B, and Bz) were taken with a cork borer 8 mm, indiameter., It was not 
possible, however, to obtain more than one sample from the center position of the posterior 
