Page:Sea and River-side Rambles in Victoria.djvu/29

10 with, and by them there can be little doubt that progression is effected. Their mechanism, we learn from Gosse, is very simple. At the bottom of a furrow in each ray are rows of minute pores, through which the suckers are protruded, the base of each sucker being expanded into a little globular vesicle, which lies above the pore in the interior of the ray; the walls of this vesicle are muscular, and therefore contractile, and it is filled with a fluid. When an animal wishes to protrude and extend any given sucker, it contracts the vesicle at its base by an effort of the will; the fluid is thus forced into the tubular stem which is therefore compelled to elongate, and on the removal of this contractile force, the fluid returns to the bladder, either by the elasticity of the tube, or probably by its muscular action, and the sucker is gradually withdrawn.

We are treading shells under our feet at every step, and as yet have said nothing of them, beautiful as they are, and must reserve it now for another chapter, since we cannot dismiss forms varied as they are graceful, with any hurried remarks.