290 MONSTROSITIES AMONG TROUT. 


These double fish are not very common, and as they die 
after the vitelline sac has been absorbed they are not seen 
by fishermen. The ratio of these deformed fish to the 1 
number of eggs in the hatching troughs was roughly esti- 
mated at twenty to twenty thousand, or one in a thousand 
eoos. 
co 
But a curious fact proved that the eges of some fish con- 
tained a larger proportion. One large blind trout had à : 
small pond to herself, and was fed daily by food presented to 
her on the end of a stick. Her eggs were kept apart, and 
out of about two thousand there were sixteen deformed fish, 
or one to one hundred and twenty-five eggs. Certain fish 
would seem to be more predisposed to produce eggs creating 
these monstrosities, and were we to ask for the cause of this, 
we should probably have to look for it in some anomaly of 
the ovary of the fish which produces the eggs. 
A deformity more common than the double fish is an 
apparent curvature of the spine. The fish instead of being 
straight, with the umbilical vesicle under him, is curved 
“Fig. 4 round so that its tail turns under, and some- 
times touches the under surface of the sac 
he is attached to. Fig. 49 represents one 
of these semicircular fish. They are obliged 
') to swim on their side, and move round n 
fouid'i in a circle, or in a spiral, without being able to 89 
straight. 
These deformities are mentioned and treated by Buckland 
in his “Fish Hatching.” He there suggests that humpbaeked 
detnr may have been caused by pressure during their 
"transport in the egg state." In the instances mentioned 
above, however, (Ce was no transport, the ova being g taken. 
_ from the fish on the spot. M 
| Out of two thousand salmon ova hatched at Messrs. Dex- 
ter & Co’s fish-farm, there were no deformities, but in another | 
lot of shout the same e mimber there were two double-headed 






















