SEA -WORMS. 191 



or four inches in length; the back is of a miiddj or mouse- 

 colour ; the sides clothed with silky hairs which reflect the 

 prismatic colours of the rainbow. It crawls by means of 

 bunches of stiff bristles, which terminate in sharp, barbed 

 claws. On its colours, as observed in the Aquarium, Mr. 

 Gosse makes the following remarks: "Perhaps it is most 

 beautiful by candle-light, where red and orange reflections 

 predominate; by day, pearly greens and blues prevail. This 

 difference is owing to the position of the light, and the angle 

 at which it is reflected. Thus, if the eye glance along the 

 bristles towards the light, which is reflected at an obtuse angle, 

 the reflected rays will be lilac, passing into ultramarine ; if 

 the angle of reflection be a right angle, the rays will be 

 green ; if the light be between the observer and the animal, 

 not directly but obliquely, so as to make the angle more or 

 less acute, t-he reflections will take yellow, orange, scarlet, 

 and crimson hues." 



The Aphrodita in crawling lifts up its tail and folds it 

 into a groove above ; the groove so formed leads to an open- 

 ing in the hinder part of the back. We hear of false bot- 

 toms, but this creature has a false back. That felt-like skin 

 on the back is merely an outer covering through w-hich is 

 filtered the water as it passes to the breathing apparatus. 



