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Part III. — Tenth Annual Be port 
monthly, is full of uncertainty ; and Dr Fulton mentions that in working 
up the returns in regard to reproduction he could come to no definite 
conclusion as to the spawning season of the halibut. Parnell, in his 
Fishes of the Forth, states that the halibut spawns in spring. J. Couch, 
again, does not refer to the subject, though R. Couch, according to Day, 
gives April as the spawning period. Buckland quotes the period given 
by Parnell, and adds that the roe is of a pale red colour and the ova 
numerous — a remark, however, which is applicable to many forms. Day 
has nothing to add to the foregoing. Mobius and Heincke observe that 
the spawning period occurs in spring, and state that Malm found in the 
Cattegat a ripe female on the 26th April. Brook gives the spawning 
season on the West Coast as from March to June. Fulton, again, in last 
year's Report,* found an advanced specimen, captured east of the Island 
of May, with the ovaries of a pinkish tinge, on the 18th of February, and 
others less advanced in June. Like other pleuronectids, therefore, the 
halibut spawns early in the year, and probably continues to May or June. 
Dr Fulton notices that the eggs were comparatively large even in February. 
In June, again, he found the ovarian ova reached 1*27 mm. in diameter, 
but they were far from ripe, as indeed were those and other specimens he 
kindly forwarded to St Andrews in May and June. No ripe example 
was seen amidst the many hundreds from Iceland and Faroe, examined on 
the pontoon at Grimsby about the middle of the latter month. The men, 
moreover, appeared never to have seen a ripe specimen. 
About the beginning of May Mr Holt kindly informed me that he had 
secured the fresh eggs of this species at Grimsby, and that they ranged 
from 3*07 to 3 81 mm. in diameter, were destitute of an oil-globule, and 
delicate to handle. The capsule had faint scribbled markings. They 
are thus the largest pelagic eggs off our shores ; indeed, Raffaele in the 
rich Bay of Naples appears to have found none over 3 mm. in diameter, 
though Wenckebach subsequently found one of 4 mm. Mr Holt mentioned 
that they collapse and burst very readily, and thought it possible that a 
large peri vitelline space is formed after fertilisation, as in the long 
rough dab. 
Immediately afterwards Dr Fulton secured ripe eggs through Mr R. 
Mackie, Assistant Fishery Officer, Peterhead, who removed them on the 
27th April 1892 from fishes which had been three days on board. The 
halibut were caught on Bergen Bank, about 60 miles off the Fair Isle, 
and 150 miles E.N.E. from Peterhead. The specimen from which the 
ova were procured weighed about 140 lbs., and the roe from 18 to 20 lbs. 
Roe 28 lbs. in weight has been found in the halibut. 
The eggs were preserved in a strong solution of picric acid, and of 
course had shrunk considerably, and the apparently mature were mingled 
with numerous unripe eggs. The perfectly ripe eggs appeared to be nearly 
circular, and had a diameter of about 3 3 mm. Those less advanced, 
though fully 3 mm. in diameter, were more or less ovoid, as usual in 
unripe forms. So far as could be ascertained, the capsule (zona radiata) 
had the same structure as in other forms, and the external surface was 
smooth and glistening. As Mr Holt pointed out, it is comparatively thin 
for so large an egg. The condition of the micropyle could not be made out. 
Along with the foregoing large eggs were many nearly uniform in size 
(1-9050 to 2-0574 mm.). It is probable that most of the eggs, which in 
a given season are ripened and shed, increase to a size more or less uniform, 
but considerably less than the diameter of the mature egg ; and that the 
subsequent increase to the mature condition takes place more rapidly than 
the previous growth. Such is the general impression, though no exact 
observations have been made. 
A large number of apparently ripe (though dead) eggs of this species 
* Page 261. 
