_ BRITISH FRESH-WATER FISHES 
source of supply that one wonders how, unless artificially 
introduced, they ever came to be there. Some are 
discovered in waters that, unless in flood or spate, are 
often almost dried up, or in inaccessible pools; others are 
found inhabiting dykes, ditches, small water courses, 
and other unlikely places. The distribution of fresh- 
water fishes, and their likes and dislikes, are extremely 
interesting, and so one might continue the fascinating 
story. Some, let it be noted, keep at the bed of the 
water, others are surface-lovers, and rarely condescend 
to go to the bottom unless for spawning purposes. 
Some are of solitary disposition, others appear to find it 
imperative, or rather essential, to adopt “ shoaling ” 
habits. 
Fishes deposit eggs, but this is not true of them all as, 
in one of the Museums at Cambridge (and doubtless 
elsewhere), there is a very wonderful specimen of a 
small Roach-like fish (although I believe it is a marine 
species), showing the female carrying her own young, 
packed inside her body like the proverbial “ Sardines in 
a tin!” A viviparous fish is surely an intensely in- 
teresting creature, and whilst they are all of supreme 
interest in their various capacities, this one in particular 
must be singled out for special mention. As a rule, 
however, eggs are laid. These may be found among 
gravel, mud, or rocks, or placed upon water plants. 
After the female has produced her eggs (and she deposits 
an abundance of them so as to guard against accidents, 
enemies, and waste), the male passes over them for 
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