based on the Principle of Cepkalizafion. 99 



at such points. One example is that of Orthopters and Neurop- 

 ters through the Mantids in the former, and the Mantispids in tiie 

 latter ; also, that of Dipters and Neuropters, through the slender 

 Tipulids of the former. The same may be exemplified among the 

 orders of Birds. The degradational feature, for example, of webbed 

 feet, or that of defective wings, may characterise the inferior species 

 of dilferent subdivisions, and so [)rodace osculant groups ; so may 

 the ampli/icative feature of great length of limb and neck, the 

 Herons among the Altrices, thus representing the Grallatores 

 among the Praecoces. 



The osculations or close approximations of classes, orders, tribes, 

 &c., are thus often connected with like expressions of the methods 

 of cephalization. 



4. Forms resulting from high and low cephalization sometimes 

 similar. — High and low cephalization often lead to similar forms, 

 the former through cephalic concentration, the latter through 

 cephalic and general feebleness ; just as a thing may be small, 

 when the material is condensed or concentrated, and equally small 

 when dilute and there is little of it. Thus the Crab has a very 

 small memberless abdomen, from a contracting of the sphere of 

 growth through concentrative cephalization ; on the other hand, 

 the Schizopod has a memberless abdomen, through a limitation of 

 the sphere of growth resulting from mere feebleness in the life- 

 system. The abbreviated memberless abdomen of the Caprellid 

 and the obsolescent spine-like abdomen of the Liraulus are other 

 examples among Crustaceans of this elliptic decephalization. The 

 Butterflies have very large wings through the amplificative method; 

 but some inferior nocturnal species have the wings narrow, through 

 inferiority of grade, on the above principle, and not properly 

 through concentration and elevation. 



There is, in general, no danger of confounding the two cases, 

 because the accompaniments in the structure of the superior 

 species, as well as those of the inferior, commonly indicate their 

 true relations, at once, to the mind that is well versed in the de- 

 partment of zoology to which the species belong ; but there are 

 many cases in which it is not safe to make a hasty decision. 



5. Uniformity of shape and size in any group greater among the 

 higher typical species than among the lower typical or degradational 

 species. — On the higher typical level in any class, order, tribe, 

 &c, the type is represented generally in its greatest number of 

 species, and always under the least extravagance of form and 

 size. Thus, Insects, the higher typical division of Inserteans, are 

 vastly more numerous in species, and less diversified in size, form, 

 and structure, than Crustaceans or Worms. And, under Insects, 



