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NOTES ON THE FRESH-WATER FISHES OF INDIA. 463 
Have they remained within the mother fish, and has their ger- 
mination been retarded so long as she continued in the exsiccated 
mud? Did she deposit them as soon as the rains set her free ? 
I cannot believe this theory to be tenable; first, because the fish 
Ihave seen removed alive from the mud had no ovainthem; and 
secondly, because the fry were so soon hatched after the setting 
in of the rains, while none of these fishes are ovi-viviparous. It 
seems more reasonable to suppose that the fertilised eggs are 
imbedded in the mud, and, as soon as the rains occur, become 
hatched out; and this would give us reason to believe success 
might result if this plan were tried with the ova of pond-fishes. 
Could large numbers of eggs be safely conveyed in dried mud to 
distant countries, a considerable amount of the present difficulty 
in their transport would have been overcome. ‘The Bishop of 
Norwich, at a meeting of the British Association in 1875, ‘‘ related 
several facts, showing that the spawn of fishes may be conveyed 
from one country to another over the sea. He knew an instance 
in which the ova of the Pike were deposited in the thatch of a 
cottage, and after haviug remained there for years, on the thatch 
being thrown into a dry ditch, which afterwards became filled with 
rain, young Pike appeared”! (Annals Nat. Hist., 1845, p. 1026). 
A most valuable discovery was made by Mr. Youle, in 1854, that 
fertilised Salmon and Trout ova could have their germination 
retarded by means of ice. He paeked the eggs in moss, which was 
placed in a side wooden box of inch pine, having perforated sides, 
and these boxes were covered over with ice, by which means the 
ova were conveyed in safety to the Antipodes, where they were 
subsequently hatched out. 
Although I have no intention of entering upon the interesting 
subjects involved in the artificial propagation of fish, I think 
it necessary to remark how—if great cold be employed in 
retarding germination—excessive warmth may have an opposite 
and very deleterious effect; and by warmth I do not allude only 
to that which is present, but to the fact of its being in pro- 
portion to what the ova would have retained in their natural 
habitat. For it cannot be supposed that the amount of heat 
which is normal to fish-eggs in the tropics is such as might with 
impunity be applied to those which are naturally hatched within 
the arctic circle of the limits of Northern Europe. Dr. Davy 
concluded from his experiments on Salmon ova, that the ova 
