5 
of Edinburgh, Session 1884 - 85 . 
of last August. At that time I went to a small fishing village called 
Sea Houses, North Sunderland, on the Northumbrian coast, and 
obtained a large number of herring ova., which I fertilised artificially 
on glass plates when on board a herring boat off the Longstone 
Lighthouse. I kept the spawn in wooden boxes sunk close to the 
shore, and was successful in keeping a proportion of them in a 
healthy condition up to the time of hatching, and for several days 
after. When I returned to the Scottish Marine Station on Septem- 
ber 3, I brought with me about a dozen newly-hatched larvae in a 
corked bottle of sea water, and some of these were alive on Sep- 
tember 11, having lived over nine days. I attempted to feed the 
larvae by putting in the water some of the small organisms taken 
by the tow-net, and those which I examined on 11th September had 
digested food in the intestine. I had previously experimented with 
herring eggs in August and September 1883, when I accompanied 
some members of the Scottish Fishery Board to the Moray Firth, 
to investigate the herring question there. In March of the present 
year also I obtained and artificially fertilised herring ova off An- 
struther, in the Firth of Forth. On neither of these occasions had 
I suitable opportunities for making a fruitful study of my material. 
At North Sunderland I spent most of my time in observing the 
living embryos at succeeding stages, and preserving examples at 
frequent intervals. These preserved specimens I have cut into 
sections in the laboratory of the Granton Station since my return. 
The rate of development in herring eggs, as in those of most 
Teleosteans, varies considerably with the temperature. The eggs 
which I studied were exposed to a temperature varying from 53° to 
58° Fahr. (1 1 0 *5 to 14°'5 C.), and they hatched on the eighth and 
ninth days after fertilisation. 
Kupffer’s vesicle, as is well known, is a small globular cavity, 
which appears at an early stage in Teleostean development between 
the posterior end of the embryo and the yolk. In the herring eggs 
with which I had to deal the structure was visible early on the 
third day, and remained visible for about eight or nine hours; on 
the fourth day it could not be seen. At the time of its appearance 
the yolk was entirely enclosed by the blastoderm, the two ends of 
the embryo almost met at the ventral side of the ovum, and the 
rudiments of the eyes and ears were formed. 
