APPENDIX B 161 



In Metazoa the separation of the cells is as a rule total, and 

 if protoplasmic continuity exists, it appears to be secondarily 

 produced. As regards their mode of cell-division, therefore, the 

 Metazoa are more primitive than the Metaphyta; yet in spite 

 of or perhaps because of this very separateness of their units, 

 there has been a much greater division of labour between 

 different kinds of units in animals than in plants. 



To sum up : the cells of the higher plants and of the higher 

 animals are both true cells they are both broadly homologous 

 with the original units of living matter. But the mode of cell- 

 division in the two groups, in so far as it concerns the separation of 

 the cells and the formation of the boundary between them, is not 

 homologous. 



11 



