Hyatt.] 142 [March 5, 



ovum. These forms are skipped and the complex colonies, 

 which arise by fission, consist of zoons completely divided from 

 each other. The cycle of transformations is not only shortened 

 by this omission, but the origin of the reproductive bodies is car- 

 ried back into the adult stages and earlier in many forms, and the 

 rapidity of the processes of complete fission due to concentration 

 produces masses of tissue and membranes in place of loosely con- 

 nected colonies as among Protozoa. 



We have not considered the structure of the cells as worked 

 out by various modern investigators, because we do not believe 

 the reticulum (Frommann) and the possible connections of proto- 

 plasm binding cells together into masses (Heitzmann) could 

 sensibly shake this result drawn from the general morphol- 

 ogy. The many disconnected, wandering cells with their inde- 

 pendent organization and functions favor this conclusion ; and 

 the sight of these and of ova in the mesenchyme of sponges, and 

 the evidence of their functions here and elsewhere in the animal 

 kingdom are sufficient to bring a candid mind to open confession of 

 the existence of exact parallelism between them and the single, 

 individualized Amoeba. 



These and other morphological facts have led, so far as we 

 know, only to comparisons between the ordinary tissue cells and 

 the adults of the amoebae, and it has been assumed that these 

 cells are the equivalents of the adult amoebae. Morphologically 

 this seems to be true, but it does not account for the physiologi- 

 cal differences between the Protozoon and the cell. The ontol- 

 ogy of the cell, its production of tissue, and the reduction of the 

 cycle of transformations cannot be explained, unless we attribute 

 to it a concentrated energy in reproduction and a tendency to 

 form complex associations much greater than that of the Proto- 

 zoon. 



Morphological comparisons show that the succession of events 

 was first growth, then fission, then the union or concrescence of 

 the divided zoons and an exchange of their complementary 

 parts ; evidently all of these influences bear upon the tissue 

 cell and influences its reproduction. Nevertheless two cells do 

 not combine previous to reproduction by fission, and whatever 

 the effect of the original impregnation may be, we are obliged, 

 therefore, to regard a young cell as a modified agamic larva-like 



