and there, which glide down with the current till they flatten out and vanish. 

 When the sun shines, each of these little whirlpools as it glides along is ac- 

 companied on the bottom by its round, gold-rimmed shadow. Often these 

 pretty spots may be seen trailing along in companies, and some stretches of 

 brook-bottom are always thickly speckled with them — appearing and gliding 

 forward and fading out in quick, ever-recurrent succession. Next to the 

 wavy, gold-laced ripple-patterns, this whirlpool-spotting is probably the most 

 universally characteristic element of the appearance of brook-bottoms in 

 sunlight. Nor are whirlpools the sole producers of this effect. Any little 

 pits in the surface of the water, such as are made by barely-floating specks 

 of debris, or by the lightly planted feet of water-skippers (Hydrobatidce), cast 

 the same sbrt of gold-rinimed shadows, though seldom in such bright, con- 

 spicuous show. These several so characteristic brook-bottom patterns might 

 be expected to occur in the background-pictures worn by brook-haunting 

 fishes. Nor have we to seek beyond the common American Brook Trout 

 (Salvelinus jontinalis) to find both wavy ripple-shadow patterns and circular 

 whirlpool-patterns in full application. The little, light-rimmed dark spots, 

 the familiar "trout spots," are 'painted' on the fish's side, above and below 

 the "lateral line," and the wavy marks along the whole extent of his back 

 and on his dorsal fin. 



There is much likeness to the 'whirlpool' spotting in the exquisite water- 

 patterns worn by certain seals (as, in some pelages, the Common Seal, Phoca 

 vituHna), which are also wholly fish-like in their smoothly graded obliterative 

 shading, and the general character of their coloration. But we do not know 

 enough about their habits and environment to say much about the special 

 functions of their markings. Other seals, again (i. e., the Bladder-nose, 

 Cystophom cristata), are marked, over full obliterative shading, almost ex- 

 actly like certain sea-fishes. That is, they are irregularly dabbled and flecked 

 with black and white and gray, in what seems to be a generalized rocky (and 

 weedy?) bottom-pattern, as seen through several feet of water. Among fishes, 

 like patterns are worn for instance by some cod. There is certainly great sig- 



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