On the comparative anatomy of the auditory ossicles of the Mammalia / by Alban H.G. Doran.

  • Doran, Alban H. G. (Alban Henry Griffiths), 1849-1927
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: On the comparative anatomy of the auditory ossicles of the Mammalia / by Alban H.G. Doran. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    in Mus, so that the malleus more resembles that of Lepus. The stapes of this family has generally long, slender, and not very divergent crura, and the intercrural canal is wanting. In the Hystricidae the great feature is the ankylosis of the malleus to the incus, already well known to zoologists. It is almost invariable in the adults of that family. The manubrium is very broad, and the inner edge above the processus muscularis is very thick. The varieties among the different genera are trifling: the head of the malleus is produced forwards to an extreme degree in Aulacodus, Capromys, and particularly in Chinchilla, but less so in the porcupines and the agouti. The stapes is always proportionally small, with stout and not very divergent crura; a bony intercrural canal occurs in many genera, but is an inconstant feature in individual specimens of the same species. As the ankylosis of the two outer ossicles occurs in Bipus, whilst the head of the malleus remains small and unproduced, and that bone possesses a wide lamina, it must be considered intermediate, as far as those little bones are concerned, between the Muridae and Hystricidae. As occurs in other orders, the fossorial members of the Eodentia pre- sent great peculiarities in their ear-bones. In Geomys the malleus some- what resembles that of Marmotta; the stapes is remarkable for the large bulla on its base. Rhizomys and Ellobius approximate most to the rats, Bathyergus to the Hystricidae, which it exceeds in the degree of fusion of the malleus to the incus, which latter bone, however, differs in form from the same in that family. In Spalax the malleus approaches the more central type of Castor or Lepus; but the stapes is of a very unique type, somewhat similar to that of Chrysothloris, except that one crus is quite straight and very divergent. In both species of Elephant the large ossicula appear rather like the modified ear-bones of certain rodents than like any ungulate. There is neither the lamina or long manubrium mallei, nor the thick and diver- gent processus brevis incudis, nor the quadrilateral stapes frequent among the large Ungulata; on the other hand the short, broad-based manubrium, the thin, short, and hardly divergent processus brevis of the incus, and the wide intercrural aperture of the stapes are characteristic in Elephas and common among the Eodentia. In the Hyuaces the ear-bones bear a slight affinity to those of the horse, but none of any importance to the common types among the Ungulata or Eodentia. The ossicles of the remaining groups of the Mammalia will be described in a subsequent communication.
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