MARINE FOOD FISHES 113 
In certain tropical flat fishes the eye appears to 
travel right through the head to the upper surface. 
This is due to the fact that in these fish the fin is pro- 
longed on to the head. At first one eye is on either 
side, but when the cranium rotates the eye from under- 
neath is carried through the fleshy part of the fin. 
Attached to the biological station at Port Erin in 
the Isle of Man, is a fish hatchery. Here, in two large 
ponds some four hundred plaice spawn every year. The 
spawning extends over a period of about six weeks, and 
during this time the floating eggs are periodically 
collected by means of a large surface net. The eggs are 
then transferred to the hatchery and in due course the 
larval fish that hatch are turned into the sea. In 1910, 
over eight million larvee were thus hatched and released 
during the season. As might be expected, several eggs 
escape collection. These hatch, and grow to small plaice 
in the ponds. In April and May, 1909, through the kind- 
ness of Professor Herdman and the assistance of Mr. 
Chadwick, I was able to collect several of these plaice 
larvee and obtain photographs of them in all stages of 
their transformation. 
Until my arrival at Port Erin, I had no idea that 
I should have such a grand opportunity for photograph- 
ing these larvee, and, in consequence, was unprovided 
with a suifable apparatus for the work. With the 
assistance of the local carpenter, however, I constructed 
a wood, wire and brown-paper extension to my reflex 
camera, and using an acetylene bicycle lamp as an 
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