Abstract
Various classifications of Vertebrata have been proposed, but agreement has been reached on only one point—i.e. that this great group is essen- tially divisible into two unequal sections: (1) The jawless Agnatha (composed of a small number of primitive but highly specialised fish-like animals), and (2) the Gnathostomata, which embraces all other vertebrates from the true fishes to the Mammalia, including Man. In the past each of these distinctive assemblages has been sometimes accorded the rank of sub-phylum, but, however radically they differ in their buccal and visceral skeletal anatomy in the adult, such an arrangement seems untenable when we consider the criteria on which the three more primitive chordate sub-phyla have been erected and, equally, when we survey the many fundamental similarities existing between these two craniate groups. In recent years there has been a tendency to consider the Agnatha and Gnathostomata as ‘branches’, ‘groups’, or ‘super-classes’ of a single, and final, sub-phylum of the animal kingdom, and that is the arrange- ment followed here.
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© 1962 Macmillan & Co Ltd
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Parker, T.J., Haswell, W.A. (1962). Sub-Phylum Craniata (Vertebrata). In: Textbook of Zoology Vertebrates. Palgrave, London. https://doi.org/10.1007/978-1-349-00198-9_6
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DOI: https://doi.org/10.1007/978-1-349-00198-9_6
Publisher Name: Palgrave, London
Print ISBN: 978-1-349-00200-9
Online ISBN: 978-1-349-00198-9
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