14 THE SURVIVAL OF THE UNLIKE. [l. 



mal-like than plant -like. The stage in which this life- 

 plasma first began to assume plant- like functions is 

 closely and possibly exactly preserved tons in that great 

 class of organisms which are known as mycetozoa when 

 studied by zoologists and as myxomycetes when studied 

 by botanists. At one stage of their existence, these or- 

 ganisms are amoeba -like, that is, animal -like, but at 

 another stage they are sporiferous or plant -like. The 

 initial divergencies in organisms were no doubt con- 

 cerned chiefly in the methods of appropriating food, 

 the animal -like organisms apprehending their food at 

 a more or less definite point, and the plant -like or- 

 ganisms absorbing food throughout the greater or even 

 the entire part of their periphery. It is not my purpose 

 to trace the particular steps or methods of these diver- 

 gencies, but to call your attention to what I believe to be 

 a characteristic distinction between the two lines of de- 

 velopment, and one which I do not remember to have 

 seen stated in the exact form in which it lies in my mind. 

 Both lines probably started out with a more or less 

 well marked circular arrangement of the parts or organs. 

 This was consequent upon the peripheral arrangement of 

 the new cells in the development of the multicellular or- 

 ganism from the unicellular one. A long line of animal 

 life developed in obedience to this peripheral or rotate 

 type of organization, ending in the echinoderms and 

 some of the moUusks. This type long ago reached its 

 zenith. No line of descent can be traced from it, ac- 

 cording to Cope. The progressive and regnant type of 

 animal life appeared in the vermes or true worms, forms 

 which are characterized by a two-sided or bilateral, and 

 therefore more or less longitudinal, structure. The ani- 

 mal-like organisms were strongly developed in the 



