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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    cranial cavity for the lodgement of the cerebrum and cerebellum are inmany Mammalia, e. g. the Dolphin, Horse, Seal, Cat, &e. separated by a bony tentorium prolonged inwards from the poste- rior part of the parietal bones. A bony falx, as in the Ornithoryn- chus, is seldom met with. The openings for the nerves exhibit various relations, those which are separated in Man sometimes co- alescing into single apertures, others, on the contrary, remaining distinct, as the foramina incisiva. These intermaxillary apertures are particularly large in the Ruminantia, the Ornithorynchus, &c. but small in the Apes, and completely absent in the Cetacea. The eomparison of the form of the skull of the higher Apes with that of Man is a subject of much interest. Young Orang-utangs and Chimpanzees, like all young animals, have a very rounded form of skull; and owing to the slight development of the jaws, the relation of the cranial to the facial portion ap- proximates more closely to that of the human subject; but, as they grow up, very strong muscular ridges are developed from the skull, and the proportion of these parts then becomes equal. The crani- um of a full grown Orang-utang nearly equals that of Man in size, but the capacity of its cavity is considerably less. The skull of the Chimpanzee ranks next to the human cranium, and there are even forms of the latter, as of persons born deficient in brain and intellect, which sink to the same proportions as those of the Chim- panzee. The distinguishing osteological characters in the skull of the Orangs (S. satyrus and troglodytes) from that of Man-are as follows—There is a remarkable interval between the canine and incisor teeth in the upper, and between the canine and molar teeth in the lower jaw; the original development of the intermaxillaries is much more conspicuous, and the foramina incisiva are removed further back from the incisor teeth; the foramen magnum, which in Man falls immediately behind a median line drawn transversely across the base of the skull, lies much further back and is more slanting ; the articulating condyles of the occipital are smaller; the petrous bone and the jaws are much more strongly developed ; the nasal bones are flattened and blended together; the mastoid and styloid processes of the temporal, and the crista galli of the ethmoid are wanting. The Vertebral Column exhibits great constancy in the num- ber of vertebre in its cervical region. There are most gener- ally seven; Manatus and Rytina have six, the three-toed Sloth has nine cervical vertebra, both of these being very rare exceptions. c