MODERN BIOLOGY 415 



Owen is generally counted as England's greatest comparative anato- 

 mist. His activities were extraordinarily many-sided, and, thanks to his 

 position as head of one of the world's largest museums, he had particularly 

 favourable opportunities for investigating a quantity of rare animal forms, 

 both still existing and extinct, which he described in essays illustrated with 

 very fine and carefully drawn pictures. Among these special investigations 

 may be mentioned his description of the nautilus — the first specimen that 

 had ever been seen of the animal itself, the shell of which, however, had 

 been known since antiquity, and, further, the anatomy of the Brachiopoda 

 and the lung-fishes. Furthermore, he made a thorough study of the gorilla 

 and certain other rare forms of the ape family and the curious finger-animals 

 from Madagascar; and amongst fossil forms, the Saurian bird, Archnsop- 

 teryx, and the extinct giant birds of New Zealand. His monumental work 

 on dental forms in the Vertebrata should also be recorded. 



Homology and analogy 

 On the basis of this unique wealth of material he built up a number of theo- 

 retical speculations upon the organization of the entire animal kingdom, 

 which had a great influence on the biology of the succeeding age. In one of 

 the courses of lectures which he as curator of the Hunter Museum had to 

 give each year on the subject of comparative anatomy, he takes as his start- 

 ing-point his predecessor's plan of comparing the same organ through all 

 the animal groups and combines it with Cuvier's principle of examining the 

 mutual relationship of the different organs in one and the same animal form 

 in order to be able thus to ascertain the causes of the changes that the organs 

 have undergone in the different animal types. As a matter of fact, he adheres 

 to Cuvier's type theory throughout, condemning Bonnet's simple evolutional 

 series covering the entire animal kingdom. In making this comparison, he 

 proves that the same function can be exercised in different animal forms 

 partly by similar and partly by entirely dissimilar organs; the dragon-lizard 

 flies with its outstretched ribs, the flying fish and the bird with their extremi- 

 ties, the insects, again, with folds in the skin, which were originally gills. 

 This last idea, according to his own statement, he got from Oken; the gills 

 of the fishes and the lungs of the higher animals possess the same function, 

 but are not the same organs; rather the swimming-bladder and the lungs 

 correspond to one another, as is proved by the lung-fishes. This contrasting 

 relation between the function and the character of the organs he expresses 

 by the terms "analogy" and "homology"; "analogue" denotes "a part 

 or organ in one animal which has the same function as another part or organ 

 in a different animal," and "homologue" denotes "the same organ in dif- 

 ferent animals under every variety of form and function." The homologies 

 are of course the object of his special interest, chiefly those in the Verte- 

 brata, the bone-structure of which he made the subject of a special work. 



