660 ZOOLOUY SECT. 



from the most obvious absurdities of Oken, was resuscitated and 

 developed by Sir Richard Owen (1803-93) in his Report on the 

 Archetype and Homologies of the Vertebrate Skeleton, published 

 in 1846. He also founded his generalisations on the structure of 

 the adult or late embryonic skeleton in the higher groups, 

 neglecting the unsegmented crania of Cyclostomes and Elasmo- 

 branchs and of the higher Vertebrate embryo. In his view, 

 the limb-girdles are modified ribs, the shoulder-girdle belonging 

 to the " occipital vertebra," while the limbs themselves are 

 " diverging appendages," or uncinates. 



Owen's chief services to Zoology were, however, his numerous 

 and brilliant anatomical researches, such as those on Nautilus, 

 on Apteryx, and on the structure and homologies of the teeth in 

 the entire vertebrate series ; and his palaeontological investigations, 

 especially those on Archaeopteryx, on the fossil Mammals of 

 Australia, and on the Dinornithidae and other flightless Birds. 

 His conclusion, from the examination of a single fragmentary 

 femur, that there had existed in New Zealand a Bird larger and 

 heavier than the Ostrich a fact then practically unknown forms 

 one of the most famous stories in natural history. His contri- 

 butions to classification were not happy ; he took the nervous 

 system as the basis of his larger divisions, classifying Mammals, for 

 instance, according to the presence or absence of a corpus callosum 

 and of convolutions, and placing Man in a separate sub-class as the 

 supposed sole possessor of a posterior cornu and hippocampus minor. 

 He rendered great service to philosophical Zoology by pointing out 

 the distinction between homology and analogy, and by the pub- 

 lication of his great text-book on the Anatomy and Physiology of 

 Vertebrates. 



The chief successor of Cuvier in France was Henri Milne- 

 Edwards (1800-85), who enunciated the principle of the 

 division of physiological labour, and modified the classification 

 of Cuvier in several particulars. He separated Tunicates from 

 Mollusca proper and united them with Polyzoa under the name of 

 Molluscoida, and he divided Vertebrates into Allantoidea and 

 Anallantoidea, according to the presence or absence of an allantois ; 

 in so doing he took the important step of separating Amphibia 

 from Reptiles, a step in which De Blainville had been his only 

 precursor. His learned Lemons de VAnatomie et de la Physiologie 

 comparees is a storehouse of information on the structure and 

 functions of animals. 



It was not until about the middle of the century that further 

 increase in the knowledge of the lower animals resulted in the 

 gradual dismemberment of Cuvier's unnatural Branch Radiata. 

 Frey and Leuckart established the group Ccelenterata, and 

 placed Echinoderms apart ; Wiegmann removed Rotifera from 

 Protozoa to Vermes ; Vaughan Thomson defined the Polyzoa, 



