1^0 LIFE AND DEATH. [III. 



eggs are extruded.' In Julin's account^, upon which Gotte 

 bases his statements, there are, however, some not unimportant 

 differences. For instance, the eggs are not extruded at all, but 

 embryonic development takes place within the body of the 

 mother, which has previously undergone spontaneous division 

 into several pieces. In this case, the eggs differ from those of 

 the other female form, inasmuch as they do not constitute the 

 whole of the endoderm, but are embedded (as was stated above) 

 in a fairly voluminous granular mass at the expense of which, 

 or at least by means of which, they are nourished ; for thej^ 

 increase considerably in size during their development. But 

 not only this granular mass, but all the layers of the body of 

 the mother, even the ectoderm, persist during the embryonic 

 development of the offspring. Indeed, the ectoderm must 

 continue to grow during the division of the mother animal, for 

 it gradually covers in the products of division on all sides, and, 

 by means of its cilia, causes the animal to swim about in the 

 fluids of its host. After some time the cilia are lost, and the 

 separate parts into w^hich the mother animal has divided, fix 

 themselves upon some part of the body-cavity of the host ; the 

 young become free, and the remains of the body of the mother 

 probabl}?- disappear b}^ dissolution and resorption ^. In this 

 case the remains of the mother animal seem to be, to some 

 extent, consumed by the embryos, — a process which some- 

 times, although very rarely, happens elsewhere. We can 

 scarcely consider this as a primitive arrangement, or look upon 

 it as a proof that ' reproduction ' has a necessarily fatal effect 

 upon the Polyplastid organism. 



In the male, the mass of spermatozoa does not swell out the 

 body to such an extent that its walls must give way and thus 

 permit an exit, but the large ectoderm cells atrophy sponta- 

 neously at the time of maturit}', and as they fall off, exit is given 

 to the spermatozoa here and there. In this instance also the 

 dissolution of the body is not a consequence of reproduction, 

 but reproduction can only take place when the dissolution of 

 the body has preceded it ! 



\ 1. c, p. 37. 



~ Julin does not enter into further details on this point, and it is not 

 quite clear at what precise time the cells of the ectoderm atrophy ; but 

 this is irrelevant to the origin of death, since the granular mass sur- 

 rounding the egg-cells at anj' rate belongs to the soma of the mother. 



