MODERN BIOLOGY 501 



therefrom the fins of the fishes on the one hand, and the motive organs of 

 the land-animals on the other. He supplemented this investigation with an- 

 other on the scapular apparatus and the pelvis, in which the bones of these 

 parts are similarly compared. The last and biggest section of this work is 

 called "Das Kopfskelett der Selaclner" and is described by Gegenbaur's dis- 

 ciples as the climax of his production. In it he examines and condemns after 

 the style of Huxley the old theory of the skull's being composed of verte- 

 bra:; instead he makes the cranium of the sharks the archetype from which 

 the same part in all higher vertebrates must have been derived; it comprises 

 in the sharks throughout their lives a cartilaginous capsule and is formed 

 of the same elements also in the higher vertebrates, while the latter's de- 

 finitive cranium is constructed with the co-operation of a number of covering 

 bones, originating in the skin. On the other hand, the visceral skeleton of 

 the head — gill-arches and jaw-bone — is compared with the ribs, so that 

 a part of the head, at any rate, possesses a segmented character. In conjunc- 

 tion with these skeletal investigations Gegenbaur also carried out a number 

 of comparative studies in the sphere of the anatomy of the nerves and mus- 

 culature and the organs of digestion. The entire results of his research work 

 he collected in that great work which was published towards the close of 

 his life, Verglekhende Anatomk der Wirbeltiere, in which he gives the most 

 complete expression to his ideas and aims. As parts of this work he added 

 his previously published text-books Grundxtige and Grundriss der vergleicben- 

 den Anatomie, which present his views, in concise form, and the method of 

 presentation and the contents of which have been imitated by many later 

 authors. In these, as also in his monographs, Gegenbaur's style is always 

 heavy and sometimes hard to understand, which his admirers held to in- 

 dicate depth of mind; nevertheless, consistency and set purpose are the most 

 conspicuous features in his scientific writings — which indeed explain their 

 success with his contemporaries. 



Gegenbaur s general principles 

 In some essays written late in life Gegenbaur sets forth the principles 

 on which he considers that biological research should be carried out. To 

 him, comparative morphology is the essential science, not to say the only 

 road to the knowledge of life; and the final goal of this knowledge is the 

 determining of the mutual relationship of the different life-forms by dis- 

 covering their common origin. "The ultimate aim is phylogeny," he says 

 in an account of the relation of anatomy to ontogeny. After the fashion of 

 Darwin, he ascribes the actual formation of species to natural selection, 

 though, practically speaking, he does not discuss this problem, but con- 

 fines himself to tracing the individual organs back to common archetypes, 

 which he seeks in the lower organisms, in the vertebrates particularly in 

 the sharks. Investigations in homology with a phylogenetical purpose are 



