190 Prof. J. D. Dana on Cephalization. 



to the lowest Fishes, admits of no other case of analogous trans- 

 fer*. In the Walrus the tusks have some locomotive functions, 

 as they serve to rest the fore part of the animal, or its head, on 

 the ice while the body is in the water ; but this is an example 

 under the second method. The feet are wholly absent in Snakes, 

 and the ribs aid in locomotion ; but this is only a degradation 

 of the Vertebrate type, and not decephalization by the first 

 method. In most Fishes, and in Whales, the locomotive func- 

 tion is transferred mainly to the elongated vertebrated posterior 

 extremity of the body — a case of degenerative degradation similar 

 to the last, and analogous also to the multiplicative. 



It is of sufficient interest in this connexion to be repeated 

 here, that among Mammals the four orders of Megasthenes ex- 

 hibit in their fore limbs four distinct grades of cephalization : in 

 the Quadrumanes these organs serve for carrying their young, 

 supplying the mouth with food, taking their prey, and for loco- 

 motion ; in the Carnivores, for taking their prey and. for loco- 

 motion ; in the Herbivores, for locomotion only ; in Mutilates, 

 for fish-like locomotion, the members having the degraded form 

 of fins. 



II. Articulates. — In the subkingdom of Articulates, the three 

 classes are Insecteans, Crustaceans, and Worms : the first includes 

 Air-breathing species {Insects, Spiders, and Myriapods), and the 

 second and third the Water-articulates. Examples of cephali- 

 zation by the first method occur in the first two of these classes. 

 They cannot in the third, because Worms have no proper feet, 

 and are not a type with closed limits, but one admitting of in- 

 definite multiplication of parts behind, and therefore open pos- 

 teriorly. 



1. Insects, the highest of the three orders of Insecteans, have 

 three pairs of mouth-organs and three pairs of legs. As the 

 wings belong to the same segments of the body with two of the 

 pairs of feet, they are not to be counted ; for the transfer noted 

 is, in fact, a transfer of segments of the body along with their 

 appendages. 



Passing down from Insects to Spiders, the mouth loses one 



* To the zoological characteristics of Man, mentioned in the writer's 

 article on Mammals (that is, the extreme cephalization of his system, and 

 the erect form connected therewith) should be added the following, — that, 

 while in the Quadrumanes the feet are clasping or prehensile feet, in Man 

 they are simply organs of support and locomotion. The foi-mer fit the 

 Apes for their climbing habits, the latter empower Man for human duty. 

 The discussion, now in progress, whether the hind limbs of the Gorilla 

 terminate in hands or in true feet ("in no sense hands," in the words of 

 Prof. Huxley) is of small importance in this connexion. 



The writer's view of the characteristics of Man depending on his spiritual 

 nature are given in SilUman's Journal, vol. xxxv. p. 452. 



