166 Secrets of the Ocean [FOURTH WEEK 



ward, the sucking cups lined with their cruel teeth closing 

 over the inequalities of the bottom. The creature may 

 suddenly change its mode of progression and shoot like 

 an arrow, backward and upward. If we watch one in its 

 passage over areas of seaweed and sand, a wonderful 

 adaptation becomes apparent. Its colour changes con- 

 tinually; when near sand it is of a sombre brown hue, then 

 blushes of colour pass over it and the tint changes, corre- 

 sponding to the seaweed or patches of pink sponge over 

 which it swims. The way in which this is accomplished 

 is very ingenious and loses nothing by examination. Be- 

 neath the skin are numerous cells filled with liquid pigment. 

 When at rest these contract until they are almost invisible, 

 appearing as very small specks or dots on the surface of 

 the body. When the animal wishes to change its hue, 

 certain muscles which radiate from these colour cells are 

 shortened, drawing the cells out in all directions until they 

 seem confluent. It is as if the freckles on a person's face 

 should be all joined together, when an ordinary tan would 

 result. 



From bottoms ten to twenty fathoms below the surface, 

 deeper than mortal eye can probably ever hope to reach, 

 the dredge brings up all manner of curious things; basket 

 starfish, with arms divided and subdivided into many 

 tendrils, on the tips of which it walks, the remaining part 

 converging upward like the trellis of a vine-covered summer 

 house. Sponges of many hues must fairly carpet large 

 areas of the deep water, as the dredge is often loaded with 

 them. The small shore-loving ones which I photgraphed 

 are in perfect health, but the camera cannot show the 



