based on the principle of Cephalization. «S27 
distinct respiratory organs, or of different parts in the digestive 
system, etc.; or the union of the sexes in one individual, ete.; 
—a simplification which reaches its extreme limit among ‘Radi- 
ates in the Hydra, and among animals, in the Protozoans. 
6. Simplicity from equality in parts normally alike; as, equal- 
ity in the height of the teeth of some of the earliest of Tertiary 
Mammals; in the annuli of Worms. This case is related to the 
known law of differentiation or specialization, which is funda- 
mental in all development. 
Differentiation internally, as it multiplies and perfects the 
means of elaborating the structure, is attended with an increas- 
ingly higher grade of chemical change, more perfect ‘grinin ye 
and more complete en gahasts esta 3 the blood; and implies, 
therefore, improvement in all t ,& more sensitive hace 
system, and greater cephalic coast sail activity. And from the 
reverse comes the reverse effect 
9. Elliptic—Exhibited in the defectiveness, or absence, of 
Segments or members normally ga - the type of the 
order or class containing the species. The are— 
a. Incomplete, or deficient, segments or eke in either the 
aniertor, or the posterior portion of the body; as with certain 
teeth in the Herbivores, toes in the foot of the horse, one or two 
pairs of antennz in some inferior Crustaceans 
. Defective, or Ses aend senses. 
When the deficie t parts are only those that are normally 
organ or member. The foot of the apres = iptic, ridthee 
are wanti in 
Viewed on the ascending grade, this method is the completive. 
10. Phytozoic—Exhibited in a departure from the Animal-type 
ugh a participation in structural features of the ows! ed 
that is, through a plant-like arrangement of the organs.—' 
Cases are— 
a. A radiate arrangement of external organs; as in the Bryo- 
zoans and inferior Tunicates. 
radiate arrangement of internal as well as external organs; 
as in Radiates 
ty & Perfect, or nearly perfect, symmetry in the radiation, instead 
