38o THE BEGINNINGS OF LIFE. 



a faint yellowish-green and sapphire blue colour, makes 

 its appearance in different parts of the brown mass, or 

 to one side of it, and afterwards, becoming botryoidal 

 or mulberry-shaped, separates into gonidia. The brown 

 chlorophyll with the other effete contents then shrinks 

 up into a structureless, homogeneous, more or less de- 

 fined, circular nucleus, of a dark brown colour, and the 

 cell frequently projecting on one side in a conical form 

 bursts at the apex and gives exit to the gonidia. . . . 

 The gonidia are globular, ovate or spindle-shaped, and 

 of a light blue colour. They average -i^-^' in diameter i, 

 and contain, together with the blue substance men- 

 tioned, more or less also of the refractive globules, and 

 a transparent vesicle. Each gonidium is provided with 

 one or two cilia, according to its form, that is to say, 

 the globular ones present one and the spindle-shaped 



' Although this is the average size, gonidia may be met with varying 

 much in bulk. Mr. Carter says, p. lo: — 'I have already described the 

 commonest form of gonidium, but there is still another about twice 

 the size, viz. Q-jVij" ^" diameter, which, although not so frequent, 

 is nevertheless sufficiently so to show that there are two sizes more 

 common than the rest ; for we shall presently see that the gonidial 

 substance may occasionally come out as a whole, or in gonidia of all 

 sizes below its original bulk. This large gonidium generally presents 

 itself under a circular or globular form, with a single cilium, but it is 

 sometimes seen ovate or spindle-shaped like the smaller one. It must 

 be obvious to all, that a polymorphic cell^ such as the gonidium is, can 

 have no constant figure while in a state of activity ; hence at one time it 

 may be of one shape and at another of another, but when under poly- 

 morphism and the cilium has disappeared, a group of gonidia will ex- 

 hibit a strong tendency to exhibit the same kind of figure generally, 

 whatever that may be.' But just after they become stationary the form 

 of Actino^hrys sol seems to prevail. 



