Elements of the comparative anatomy of the vertebrate animals designed especially for the use of students / by Rudolph Wagner ; Edited from the German by Alfred Tulk.

  • Wagner, Rudolph, 1805-1864.
Date:
1845
Catalogue details

Licence: Public Domain Mark

Credit: Elements of the comparative anatomy of the vertebrate animals designed especially for the use of students / by Rudolph Wagner ; Edited from the German by Alfred Tulk. Source: Wellcome Collection.

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    Man, as the Bushmen-Hottentots. The nasal bones are very long and conspicuous in the Solidungula and Ruminantia, and of remark- able length in the Porcupine. The Cetacea, as the Narwhal, have a pair of very small, rounded, and somewhat asymmetrical nasal bones, situated far back. The /acrymal bone appears to be very rarely wanting, asin the Seal and Walrus, or to become confluent with adjacent bones, as in the Ornithorynchus and Echidna. It ex- ists only as a small imperforate plate in Manatus and Halicore, while in the rest of the Cetacea it is merely an appendage of the frontal bone. In the Solidungula and Ruminantia it is very large, and is frequently, as in the Stags, provided with a deep pit or groove for the reception of the sebaceous sacs. The malar bone is very seldom wanting, asin Manis; butit is very small, thin, and flatten- ed in the ordinary Cetacea. In Myrmecophaga it presents the form of a small thin scale, which is, as in the Tardigrada and in Centetes, not united by a complete zygomatic arch with the tem- poral bone. In the Sloths it gives off both above and below a free and pointed process of considerable size. In the Carnivora it is very much developed, and forms a very strong arch, convex externally. Its frontal process seldom reaches the bone of that name, and it is only in the Solidungula, Ruminantia, and Makis, that the union takes place between them so as to complete the ring of the orbit externally. It is only in the Apes that an inner plate is developed like that of Man, which circumscribes completely the orbit and zygomatic groove. The palatal bones are smallin Man and in the Apes, and most conspicuous in the Carnivora. The vomer is generally present, and is sometimes, especially in the Cetacea and Ruminantia, a perpendicular plate of considerable size. Nume- rous differences are exhibited by the superior and intermaxillary bones. The entermaxillary, which, in Man, is found only in the earliest foetal periods, occurs in allthe Mammalia, and supports the incisive teeth, except when it is devoid of teeth, as in the Rumi- nantia. It is therefore particularly conspicuous in animals provided with large incisors, as in the Rodentia and the Elephant, where it extends far backwards, abutting against the nasal bones and vomer, and more rarely still against the frontal or the malar and lacrymal bones. It is very seldom, as in the Ornithorynchus and Unau (two-toed Sloth), divided again upon each side into two portions. In many Cheiroptera the intermaxillaries are separated by a remark- able interval in the middle from each other, as in the malformation called cleft palate in Man. The dower jaw consists in the Apes,