88 



MORPHOLOGICAL DEVELOPMENT. 





components homologous with one another — no one of them 

 can be resolved into minor individualities. Its proximate 

 units are those physiological units of which we conclude every 

 organism consists. The aggregate is an aggregate of the first 

 order. 



§ 201. Among plants are found types indicating a transi- 

 tion from aggregates of the first order to aggregates of the 

 second order; and among animals we find analogous types. 

 But the stages of progressing integration are not here so dis- 

 tinct- The reason probably is, that the simplest animals, 

 having individualities much less marked than those of the 

 simplest plants, do not afford us the same facilities for obser- 

 vation. In proportion as the limits of the minor individuali- 

 tips are indefinite, the formation of major individualities out 

 of them, naturally leaves less conspicuous traces. 



Be this as it may, however, in such types of Protozoa as 

 the compound Radiolaria, we find that though there is reason 

 to regard the aggregate as an aggregate of the second order, 

 yet its divisibility into minor individualities like those just 

 described, is less manifest. Fig. 140 representing Sphcerozoum 



punctatum, one of the group, illustrates this. The sceptic- 

 ally-minded may perhaps doubt whether we can regard the 

 " cellaeform bodies " contained in it, as the morphological 

 units of the animal. The jelly-like mass in which they are 

 imbedded, is but indefinitely divisible into portions having 

 each a cell or nucleus for its centre.* Among the 



* This statement seems at variance with the figure ; but the figure is very 

 inaccurate. Its inaccuracy curiously illustrates the vitiation of evidence. 

 When I saw the drawing on the block, I pointed out to the draughtsman, 



