WHEEL-BEARERS. 237 



sixteen, and so on, by the successive cleavage of each 

 division, as fast as it is made, till these divisions are very 

 numerous. Then we begin to see spontaneous movements ; 

 the outline of the young separates in parts from the wall 

 of its prison ; folds are seen here and there, and fitful 

 contractions and turnings take place. Soon an undefined 

 spot of red appears, which gradually acquires depth of tint 

 and a definite form, and we recognise the eye. Slight 

 waves are seen crossing one end of the egg ; these become 

 more and more vigorous and rapid, and at length we see 

 that here is the situation of the frontal cilia. The mastax 

 appears, and the jaws, and soon the latter begin to work ; 

 though it must be only by way of practice, for it is hard 

 to imagine what they can yet find to masticate. 



All these phenomena have successively appeared in the 

 egg we are now watching ; and at this moment you see 

 the crystalline little prisoner, writhing and turning im- 

 patiently within its prison, striving to burst forth into 

 liberty. 



Now a crack, like a line of light, shoots round one end 

 of the egg, and in an instant the anterior third of the shell 

 is forced off, and the wheels of the infant Brachion are 

 seen rotating as perfectly as if the little creature had had 

 a year's practice. Away it glides, the very image of its 

 mother, and swims to some distance before it casts anchor, 

 beginning an independent life. At the moment of the 

 escape of the young, the pushed- off lid of the egg resumes 

 its place, and the egg appears nearly whole again, but 

 empty and perfectly transparent, with no evidence of its 

 fracture except a slight interruption of its outline, and a 

 very faint line running across. 



This is a female young : the male is totally unlike the 

 female, and is very much smaller. We can always tell 

 whether an egg is going to produce male or female young, 

 by the great difference in its size, the female being more 

 than twice the bulk of the male egg. All of one brood 



