hased on the Principle of CepJializafion. 87 



8. SimpVificatwe. — Exhibited in increased simplicity of structure, 

 and in an equality of parts tliat are normally identical. The cases 

 are — 



a. Simplicity from diminished number of internal or external 

 organs for carrying on the processes of life ; as in the absence of 

 distinct respiratory organs, or of different parts in the digestive 

 system, &c. ; or the union of the sexes in one individual, &c. ; 

 — a simplification which reaches its extreme limit among Radiates 

 in the Hydra, and among animals, in the Protozoans. 



6. Simplicity from equality in parts normally alike ; as, equality 

 in the height of the teeth of some of the earliest of Tertiary Mam- 

 mals ; in the annuli of Worms. This case is related to the 

 analytic. 



Viewed on the ascending grade, this method is the differentia- 

 tive, the fticts exhibiting which are embraced under the well-known 

 law of differentiation or specialization, which is fundamental 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 nutrition, 

 and more complete decarbonization of the blood ; and implies, 

 therefore, improvement in all tissues, a more sensitive nervous 

 system, and greater cephalic power and activity. And from the 

 reverse comes the reverse effect. 



9, Elliptic. — Exhibited in the defectiveness or absence of seg- 

 ments or members normally pertaining to the type of the order or 

 class containing the species, and arising from abnormal iveaknesa 

 in the general system, or in an organ. It is exhibited especially 

 in the degradational or inferior types. The cases are — 



Incomplete or deficient (1) segments, or (2) members, in either 

 (a) the anterior^ or (6) the poster'or portion of the body ; as in 

 the absence of some or all, of the teeth in Edentates ; of the 

 posterior limbs in Whales ; of the abnormal appendages and pos- 

 terior thoracic segments in some Schizopods or degradational 

 Macrurans ; of the antennae, either one or both pairs, in many 

 inferior Entoraostracans ; of wings in the Flea, &c. 



This method of decephalization differs from the defunctionative 

 in implying a deficiency not only of function but also of organ or 

 member. 



The incompleteness or deficiency of normal parts referred to 

 above will be better appreciated if contrasted with deficiencies from 

 other causes. The principal other causes are the following : — 



(1.) A high degree of cephalization or cephalic concentration 

 in the system. — -Thus in the crab, the highest of Crustaceans, the 

 abdomen is very small, and elliptic both in segments and members, 



