150 THE LIFE-HISTORY OF THE PILCHARD. 
September 5th, ten miles south of the Hddystone, by the crew of a 
Plymouth boat, to whom I had given bottles for carrying the eggs 
and instructions for dealing with them. Usually ripe pilchards are 
caught in mackerel nets, pilchard nets not being often used at a 
sufficient distance from land during the season when pilchards spawn, 
but in this case the boat was using pilchard nets and fishing for 
pilchards. The total catch amounted to 2,200 fish, but only a few 
of those were ripe. In the bottles when brought to me there were 
a considerable number of dead eggs at the bottom, but several thou- 
sands of living ones floating at the surface of the water. These 
were fertilised and developing, the blastoderm having extended 
already half round the yolk. 
The characteristics of the eggs I have described in previous 
papers. In these, the divided yolk, single oil-globule, and large 
perivitelline space were present exactly as in the eggs obtained from 
the sea, or the unfertilised eggs taken on previous occasions from the 
fish. A drawing of one of these eggs actually taken from the pil- 
chard and artificially fertilised, agrees in all respects with the figure 
which I published as the egg of the pilchard in Plate 5 of Vol. I of 
this Journal. But among these eges I noticed one which presented 
an interesting variation or abnormality. This egg is represented in 
Fig. 1. It resembled the other eggs in all respects except one, namely, 
that instead of the normal large space between the envelope or 
Fia. 1.—Abnormal, but healthy, egg of the pilchard, having small perivitelline space. 
vitelline membrane and the egg proper, there was a narrow space as 
‘in the majority of other pelagic eggs, for instance the mackerel or 
plaice. I once found an egg showing this character among those 
taken from the sea by the tow-net, and thought it was the egg of 
some other species, its parentage being unknown. It is now clear 
that it represents an occasional variation in the egg of the pilchard. 
I kept this egg separate until it was hatched, and found the larva 
