INTERESTING CITIZENS OF THE GULF STREAM 



83 



markable structure and habits to the 

 presence of sharks. This is the slender 

 Shark Sucker (Plate VI), which has the 

 anterior portion of its body horizontally 

 flattened, and a remarkable oval struc- 

 ture, with movable slats like those of a 

 blind, on the top of its head. With this 

 apparatus it attaches itself firmly at will 

 to the shark's broad side and thus as a 

 "dead head" passenger is transported 

 through long stretches of ocean without 

 any effort on its own part. 



The Shark Sucker is boldly and very 

 beautifully striped with black and white, 

 but can change its color almost instantly 

 to a dull, uniform gray matching the side 

 of the shark to which it is clinging. It 

 sometimes attaches itself also to other 

 large fishes, such as the Tarpon, or to 

 turtles. 



A related species, the true Remora, is 

 found clinging to those sharks which 

 swim through the high seas far from 

 shore. A third is found clinging about 

 the gills of spearfish or marlin swordfish, 

 as they are called by California anglers. 

 A fourth, with very large and strong 

 sucking disk, has been found attached to 

 whales. 



All of these may, loosely speaking, be 

 called Remoras. They are sometimes 

 erroneously spoken of as "Pilot-fish," for 

 the Pilot-fish is an entirely different 

 small species related to the Amber Jack, 

 which swims in front of or alongside of 

 sea-going sharks and is vertically banded 

 with black. 



THE REMORAS ARE OXE OE OCEAX's 

 MVSTERIES 



Among the fishes of the world the 

 Remoras occupy the position of a genius 

 with unknown ancestry. There is noth- 

 ing else like them, and to what manner 

 of fishes they may be related is one of 

 the mysteries of old ocean. 



Fish life of the shallow pools so often 

 found along a rocky shore at low tide 

 will repay careful study. Such a pool 

 may be a few yards long, with a very 

 irregular outline, full of nooks and cran- 

 nies, and a few square feet of sand cov- 

 ering its lowest point. 



Here the young of several types of 

 fishes act out in miniature the drama 

 which their elders are playing on the 



reef. Only the villains of the play, the 

 larger predaceous fishes, are absent, at 

 least for the present, until the returning 

 flood inundates the isolated pool to make 

 it once more a part of the big salt water, 

 and we retreat up the beach. 



The stage setting is extremely simple : 

 the jagged blackish bottom of the pool, 

 small area of gray- white sand, a little 

 patch of brownish seaweed in one place, 

 either growing there or drifted in at the 

 last high water. From a distance half a 

 dozen small fishes are visible, swimming 

 actively about. 



Nearer view shows them to consist of 

 two or three Sergeant Majors (Plate 

 VIII), instantly recognized by the black 

 and yellow uniform in vertical stripes ; 

 a couple of Beau Gregorys, with bright 

 blue heads and yellow tails separated by 

 a slanting line of demarcation, and a 

 young Wrasse striped lengthwise with 

 black on a pale ground. 



THE WRASSE CHAXGES ITS COEOR 

 IXSTAXTLV 



If one attempt to catch a fish of either 

 of the former species, it displays great 

 alertness and agility, dodging about the 

 many projections and irregularities of 

 rock. But now we have the Wrasse cor- 

 nered and believe we have it in an in- 

 stant, when suddenly it has disappeared. 



Surely it did not dodge past and make 

 good its escape in that way. Where can 

 it be? Two or three minutes of careful 

 scrutiny are rewarded. There it is, mo- 

 tionless, squeezed into a crevice of the 

 side of the pool just large enough to 

 hold it. 



Swimming actively about, it was 

 scarcely less conspicuous than the Ser- 

 geant Majors, but it has now, further- 

 more, changed color, so as to have a very 

 low visibility in its sheltered nook. Here 

 we have an illustration in detail of how 

 various theoretical types of coloring work 

 out. While swimming about with them 

 the Wrasse had a conspicuous immunity 

 pattern like the Sergeant Majors; now. 

 in the twinkling of an eye, it is a con- 

 cealingly colored fish. 



THE SAXD ELOUXDER DEElES DETECTION 



We have been speaking of fishes which 

 no one will hesitate to admit are conceal- 



