106 



the corpus callosum, in a primary subclass, under the name of 'Pla- 

 centalia'; the rest form the subclass * Implacentalia,' and this includes 

 the orders Marsupialia and Monotrema. For a further development 

 of these views, and of the organization of the Implacentalia, I may 

 refer to Professor Owen's admirable memoir ' On the Osteology of the 

 Marsupialia' in the Transactions of the Zoological Society, and to the 

 articles ' Monotremata' and ' Marsupialia ' in the Cyclopaedia of Ana- 

 tomy and Physiology. 



Professor Owen further displayed modifications of the Cuvierian 

 system on anatomical grounds, in his paper on the Dugong in the 

 Proceedings of the Zoological Society for 1838, in which he sepa- 

 rated the Herbivorous from the true or Carnivorous Cetacea. 



The anatomical and palseontological evidence for the association 

 of the Ruminantia with other hoofed quadrupeds having the toes in 

 equal number, in one natural order, called Artiodactyla, and for the 

 grouping together of other hoofed animals with the toes in unequal 

 number, in a second order called Perissodactyla, is given in the 

 Quarterly Journal of the Geological Society for November 1847. 



In regard to that family of Quadrumanous Mammalia which ap- 

 proach most nearly to Man, much obscurity prevailed at the close of 

 Cuvier's labours. That great naturalist places the Orang-utan at 

 the head of the order, from being acquainted with only the immature 

 condition of the Chimpanzee. The knowledge of the osteological 

 and dental characters of the adults of both forms, of their true facial 

 angle and cerebral capacity, were first made known in ProfessorO wen's 

 memoirs printed in the Zoological Society's Transactions ; and here 

 most of those characters which were supposed to approximate these 

 animals most nearly to Man, are shown to be transitory, and peculiar 

 to the young state of the animal with deciduous teeth. 



In a second memoir in the second volume of the Zoological Trans- 

 actions, Professor Owen gives the requisite details of the change of 

 dentition, and describes a second species of Orang from Borneo 

 (Pithecus morio). In a third memoir the cranial and dental characters 

 of a second species of Chimpanzee (Troglodytes gorilla), of formidable 

 strength and stature, discovered by Dr. Savage, are detailed in the 

 third volume of the Zoological Transactions, to which Professor Owen 

 has since added two memoirs descriptive of the entire skeleton of the 

 Troglodytes gorilla, and the relative capacities of the cranium of the 

 Orangs, Chimpanzees, and the different varieties of the human race. 



With regard to the class of Birds, I may refer to Professor Owen's 

 monograph on the Anatomy of the Toucan in Mr. Gould's works on 

 the Rhamphastidse ; to his memoirs on the Anatomy of the Horn- 

 bill in the first volume of the Transactions of the Zoological Society ; 

 and to two elaborate monographs on the Anatomy of the Apteryx 

 Australis, in the same Transactions. 



The comparison of the organization of the latter remarkable species 

 with that of the larger struthious birds, and, above all, the accessions 

 to the same wingless order which we owe to Professor Owen's memoirs 

 on the fossil remains of the Dinornis and Palapteryx obtained from 

 the Islands of New Zealand, supplied him with the requisite grounds 



