GENESIS OF MAN. 61 



having failed to unite upon any absolutely constant character as a 

 condition to its application, the use of it here is justifiable, not- 

 withstanding the ease with which the human races hybridize, and 

 no matter what theory may be preferred of their origin or rela- 

 tionships. Of these species he makes out twelve, and advances an 

 interesting theory of their origin and geographical distribution 

 over the globe ; but upon this new field we can here follow him 

 no farther. 



In casting a retrospective glance over the vast subject thus 

 hastily passed in review, there are a few salient points which will 

 have most probably, in an especial manner, struck the mind of the 

 reader. 



One of these is likely to be the great brevity of the anthropo- 

 genetic line, — considering the variety and multiplicity of living 

 forms found on the globe. We perceive that of the seven sub- 

 kingdoms of animals now recognized, only three are touched by 

 it, viz : — the Protozoa, Worms, and Vertebrates. The zoophytes, 

 echinoderms, anthropods, and mollusks all branch off either below 

 or at the worm stage, and the transition from the Tunicata, a 

 worm-form, is direct to the vertebrata. This, when adequately 

 appreciated, is an astonishing fact, and one which would never 

 have been conjectured but for positive anatomical evidences. 

 Those who believed in a law of development were looking vainly 

 for proof of the derivation of the different types one out of anoth- 

 er, and discussing which should be considered lowest, the articu- 

 lates or the mollusks. They expected to find proof of a series 

 with the radiates at the bottom and the vertebrates at the top. 

 The truth, as it has at last dawned upon us, dispenses with all such 

 speculations. 



Equally surprising is the shortness and directness of the transi- 

 tion from the lowest to the highest vertebrates, from the Amphi- 

 oxus to the Ape. All the vague surmises of some extensive 

 course of descent and lineal relationship among the numerous 

 classes and orders of vertebrates are now also brought to an end. 

 The higher fishes and higher amphibians, the reptiles and the 

 birds, are all left to pursue special routes of their own ; and a brief 

 series of easy and rapid transitions through the lowest fish-form, 

 the Selachia, and the lowest amphibian-forms, the Sozobranchia 

 and Sozura, brings us at once to the lowest mammalian stage. 



