a 
| 
SEA-FISHERIES LABORATORY. 87 
examined individually. If necessary they are first separated 
into two groups, distinguished by the presence or absence of 
oil globules. Hach group is next arranged in a series of rows 
of approximately similar size on a glass slide with the aid of a 
pocket-lens, and then measured under the microscope with the 
micrometer. ‘The size of the oil globule has also to be measured, 
and its colour noted. The oil globule in the eggs of some species 
of fish, such as the weever and sole, is broken up into a number 
of small globules scattered through the yolk or arranged into 
groups. These details all aid in identifying the species of fish. 
None of the pelagic fish eggs, with the exception of perhaps 
the long rough dab and the plaice, can be identified without 
careful examination. The eggs of the long rough dab can be 
determined almost at a glance by the large size and peculiar 
appearance of an egg within an egg, due to the large perivitel- 
line space. The plaice egg is also large. It has a thick 
corrugated capsule. After some practice it is possible to 
separate the egos of the dragonet, even with the pocket-lens. 
In all cases it is advisable to examine the eggs with the micro- 
scope, and measure them with the micrometer. 
JANUARY 
Material: Coarse net, 6; Fine net, 6; Vertical net, 6 = 18 hauls. 
Coarse. Fine. Vertical. Totals. 
Rockling eggs _... so a 4 0 0 4 
Green codeggs_... a me 1 0 0 1 
Se 5 0 0 i sith 
These eggs were only present once in the January series. 
The rockling eggs occurred on January 21st, and the green cod 
on the 30th. In some years no pelagic fish eggs have been 
obtained in this month. In others, we have found rockling 
eggs as early as January 2nd. 
