64 The Mycetozoa, and 



beauties of outward form characteristic of highly organised 

 types, to attain by means of a lattice- work of cross beams 

 within the cell body that mechanical support effected 

 by transverse septa and separate differentiated cellular 

 structures for other alga and for the higher plants." 



A consideration of these structures impresses the mind 

 very forcibly with the vast inherent capacities of proto- 

 plasm. Nature had two courses open to her, if we may 

 so speak, as to the mode of dealing with protoplasm- 

 endowed as it is with its varied capacities each of 

 which she has pursued to a certain extent. In the one 

 course of development the single protoplast has remained 

 a unit, and has hi this undivided condition performed all 

 the needful work of the plant. In the other course, the 

 protoplasm has been broken up into detached parts by the 

 cell- walls, and thus a division of labour has been brought 

 about or promoted which has led to the highest results, 

 and left the unicellular organisms far in the rear. The 

 former course of development is seen in the myxies, and, 

 as we have shown, reached a great development both as 

 regards size, form, and function, in such algae as Caulerpa. 

 The other course of development is seen of course in 

 nearly all the other members of the vegetable kingdom, 

 and reaches its highest results in such vast and complex 

 organisms as our forest trees. 



One other observation naturally arises from the con- 

 sideration of these unicellular forms. We are wont to 

 trace the origin of the differentiation of parts of the 

 branches and leaves and so forth to the divisions of the 



