WHEEL-BE AREKS. 273 



acquires deptli of lint and a definite form, and we re- 

 cognise 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 situa- 

 tion 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 im 

 agine what they can yet find to masticate. 



All these phenomena have successively appeared in 

 the esrs: we are now watching : and at this moment 

 you see the crystalline little prisoner, writhing and 

 turning impatiently within its prison, striving to burst 

 forth into libertv. 



^ f 



Xow a crack, like a line of light, shoots round one 

 end of the egg, and in an instant tlie antei'ior third ot 

 the shell is forced oif, and the wheels of the infant 

 Brachion are seen rotating as i:)erfectly as if the little 

 creature had had a year's practice. Away it glides, 

 the very image of its mother, and swims to some dis- 

 tance 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 

 hyaline, with no evidence of its fracture, except a slight 

 interruption of its outline, and a very faint line running 

 across. 



Tliis 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 egs;. All 

 of one brood are of the same sex ; we never see a Brach' 

 ionus with male and female eggs at the same time 



