THE SCAFFOLDING LEFT IN THE BODY. 85 



ranks is a limpet-like cap on the tip of the tail ; the 

 lowest are sans everything; and in the intermediate 

 forms the former glory is ironically suggested hy a 

 few grains of sand or a tiny shield so buried beneath 

 the skin that only the naturalist's eye can see it. 



"When Man left the water, however — or what was to 

 develop into Man — he took very much more ashore 

 with him than a shell. Instead of crawling ashore at 

 the worm stage, he remained in the water until he 

 evolved into something like a fish ; so that when, 

 after an amphibian interlude, he finally left it, many 

 " ancient and fish-like " characters remained in his 

 body to tell the tale. The chief characteristic of a 

 fish is its apparatus for breathing the air dissolved in 

 the water. This consists of gills — delicate curtains 

 hung on strong arches and dyed scarlet with the blood 

 which continually courses through them. In many 

 fishes these arches are five or seven in number, and 

 communicating with them — in order to allow the 

 aerated water, which has been taken in at the mouth, 

 to pass out again after bathing the gills — an equal 

 number of slits or openings is provided in the neck. 

 Sometimes the slits are bare and open so that they are 

 easily seen on the fish's neck — any one who looks at a 

 shark will see them — but in modern forms they are 

 generally covered by the operculum or lid. Without 

 these holes in their neck all fishes would instantly 

 perish, and we may be sure Nature took exceptional 

 care in perfecting this particular piece of the 

 mechanism. 



Now it is one of the most extraordinary facts in 

 natural history that these slits in the fish's neck are 

 still represented in the neck of Man. Almost the 



