26 



PROFESSOR HENRY WEBSTER PARKER, ON 



bo all, of course the difference is all there, iii matter, though 

 it be beyond discovery. 



5. Opposed to variety, should be mentioned in particular 

 a degrading repetition of like parts of structure. Bilateral 

 symmetry is not included here, for it has its own utilitarian 

 and Eesthetic reasons ; nor is such specialization included as 

 tlie number of mammalian digits. The radiate arrangement 

 in plants and the lower animals has been noticed. In the 

 higher organisms the centipedes are low land-arthropods ; 

 fish, A^th very many vertebrae and digits, among vertebrates ; 

 serpents, for similar reason, among reptiles. The piinciple 

 is famihar as illustrated in repetitious rhetoric, and in the 

 superiority of free styles of architecture over those Avith a 

 formal multiplication of like parts. The principle has a 

 limited but important application to man in his relation to 

 creatures physically nearest him ; namely, the old distinction 

 between bimanous and quadrumanous, which no new classi- 

 fication can efface. Here, however, it is not so much a 

 matter of elemental structure as of a great range of function 

 in the human hand, and also of plan of life, which in man 

 is non-arboreal. 



6. A special point may be made of prolonged repetitious 

 structure posteriorly. A dragon-fly, with its gauzy wdngs, 

 swift flight, and falcon habits, w^ould seem more noble than 

 a beetle, but its lengthened abdominal segments and other 

 reasons reduce it to near the foot of its sub-class. As the 

 principle bears on man's zoological place, it may be noticed 

 that, as a group, the quadrumana are tailed, long-tailed ; and 

 if the highest have essentially the human coccyx, it is equally 

 true that some of the lower monkeys have other striking, 

 though no more important, correspondencies to man, e.g,^ in 

 the special arrangement and length of hah* on crown, jaw, 

 and chin. There are all degrees of caudal development, dis- 

 tributed variously from the human embryo down throughout 

 vertebrates, including the adult frog in which the tail wholly 

 disajDpears; so that the phrase "tailless anthropoid" may 

 express a literal, but is not a logical conclusion. 



7. A connected criterion of importance is James D. Dana's, 

 termed by him cej)halization ; it is head domination in the 

 animal structure. Species rise in grade as the anterior part 

 of the body is relatively more developed ; the head is more 

 compacted, the jaws less projecting; there is, it may be, an 

 elevation of the forward extremity : and the fore limbs render 

 more service to tlie head. Professor Dana illustrates the last 



