Inhaltsangabe
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated.1907 Excerpt: ... state of affairs found in the carnivora supports the view expressed above that the primitive condition among the mammalia was one in which there was a large perilymph space. For we know from the smaller number of turns of the cochlea, and for other reasons, that the labyrinth of the marine carnivora is more primitive than that of the land-living animals of this order. In the ungulates the perilymph space of the canals is, in the great majority of examples, very small, and in none is it so well developed as in the primates and in the seal. It is usually more pronounced in the ungulates, however, than in the carnivora, with the exception just mentioned. In the cheiroptera and rodentia the space is hardly visible at all, and the same is true of the cetacea and marsupials, or at least of the diprotodont division of the last order. There is yet another interesting feature of the perilymph space in the canals. To whatever extent the space is present in one canal, it is always present to the same extent, or practically so, in the other two canals. This is a constant feature in all the mammalian labyrinths which have been examined. The vestibule does not lend itself so well to description as the canals and the cochlea, and differences among the various animals are not so readily noticed as in the case of the other two portions of the labyrinth. The otoliths are the most interesting feature of. the vestibule when they are of such a size as to be easily recognised by the naked eye. Unfortunately these crystals are of such a size in a very limited number only of the mammalia, among others in the seal, the sea-lion, the porpoise, and the wallaby. It is not uncommon, however, to find in the vestibule deposits of calcareous salts, which are apt to be mistaken for true ot...
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