Page:British Reptiles, Amphibians, and Fresh-water Fishes.djvu/70

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 disUkes, 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 interesting 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 54