COMPOSITE ANIMALS. 99 



like balls from the hands of a conjuror. There is 

 no apparent way of their getting outside the sac ; 

 and, indeed, they never do until the parent dies or 

 some accidental rupture is made. On the dissolution 

 of the colony they escape, and may be collected in 

 great numbers from the surface of the water. They 

 are now very interesting objects of observation. 

 One might be pardoned who was not familiar 

 with them if he fancied he had a vegetable seed 

 under the microscope somewhat resembling a small 

 bean. On the approach of warm weather the 

 statoblast begins to swell and the sides open, re- 

 vealing not indeed the first tiny germ of a future 

 plant, but a small and veritable animal, with ex- 

 panded tentacles clothed in vibrating cilia (Fig. 17s). 

 As it grows, the shell-like investment is dropped ; 

 and the creature floats away in the surrounding 

 water, the destined founder of a future colony. 



There is yet another method by which offspring 

 are secured ; and that is of a true sexual character, 

 through the several means and stages of ova, sper- 

 matozoa, egg, and embryo in the same individual. 

 In this instance, however, the young brood are not 

 at all like their parents, but rather resemble ordinary 

 H 2 



