Page:British Reptiles, Amphibians, and Fresh-water Fishes.djvu/73

INTRODUCTION Some possess barbules (as in the Barbel), others have none. Some have jaws alike on both sides, others are not alike, the mouth being situate at the end of the snout, or the snout protrudes beyond the mouth. Some have spines (as in the Sticklebacks), many, if not most, are spineless. Some have teeth, others are toothless. Some have horizontal bodies, in others the body is vertical. Some have the upper and lower sections of the tail equal, others have the tail uneven, one lobe being larger than the other. Some have a cylindrical form, others (as in the Flat Fishes, such as the Plaice), have the body flat and unsymmetrical.

Of the variety of colour and markings it is not possible to enlarge, nor of the many other features of interest regarding the external differences that exist in even our comparatively few fresh- water species. The examples that have been given will be amply sufficient to reveal the interest to be obtained from a study of these tenants of our lakes, lochs, streams, rivers, brooks, burns, and ponds, and when it is stated that in one item at least they are certainly all alike, namely, in the possession of a vertebræ, or skeleton, we must pass on.

The angler soon discovers that some fishes are shy and retiring, but that others are bold and pugnacious. Some are ravenous feeders, others are very fastidious in regard to their diet, and manner of procuring same. Some are tender-mouthed, others have strong jaws which, although sadly interfered with on occasions, does not seem to unduly upset the finnv owner. 57