File:Image from page 399 of "The cyclopædia of anatomy and physiology" (1847).jpg

English: Title: The cyclopædia of anatomy and physiology

Identifier: cyclopdiaofana0401todd Year: 1847 (1840s) Authors: Todd, Robert Bentley, 1809-1860 Subjects: Anatomy; Physiology; Zoology Publisher: London, Sherwood, Gilbert, and Piper Contributing Library: MBLWHOI Library Digitizing Sponsor: MBLWHOI Library

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Text Appearing Before Image: Skull of the Ccelogynus. ner angle there is an excavation resembling a long furrow or semi canal, which is really the infra-orbital canal. The jugal is much higher than it is broad ; the palatine extends into the palate as far forward as the first molar tooth : in the orbit it is almost hidden by the projection of the maxillary ; ne- vertheless, it is interposed between that bone and the sphenoid, and at the posterior extremity of the alveolar arch. In the Guinea-pigs (AiicEnia, Fred. Cuv.; Cavia, Ilig.; Musporcellus, Lin.), the lachrymal is large ; but it does not entirely form the upper [root of the pre-orbital ring, and the maxillary is not interrupted at this point. The pre- orbital ring is much wider than it is high. We may remark in this genus both the groove of the paca and the fossa of the agouti; but the latter is situated higher up, as in the rats. The ascending branch of the maxillary is long and narrow. The bones of the nose are broader in front than behind- The jugal only commences towards the middle of the zygomatic arch ; the palatine, which superiorly does not penetrate either into the orbit or into the temporal region, extends in the palate only as far forward as the interval between the second and the third molar teeth. In the kerodons, a small point of the frontal insinuates itself above, between the bones of the nose and the intermaxillaries, the ascend- ing branch of the latter being very long, and extremely narrow at its origin, in the Bra- zilian species. In this species, likewise, the pre-orbital ring is oval, and much elongated transversely, but formed entirely in the maxil- lary bone as it is in the Guinea-pig ; whilst in the kerodon of Patagonia the lachrymal forms by itself nearly the whole vertical portion of its arch, so that the lachrymal is necessarily of very great size. Posteriorly, the maxillary touches by its apex a long point derived from the temporal external to the palatine ; the latter, however, is enclosed between the sphe- noid and the maxillary, and mounts up into the floor of the orbit, when it is connected with the lachrymal bone. In the palate it is very deeply notched. In the capybara (Hydrochccrus, Er.xleben), the jugal is still shorter than in the Guinea- pig. The lachrymal is largely developed at the root of the vertical arch of the pre-orbital ring, but does not assist in forming it. The bones of the nose are very large and rectan- gular. The ascending ramus of the inter- maxillary, on the contrary, is extremely narrow, and is only united by its point to a point de- rived from the frontal. The inferior hori- zontal arch of the ring is broad and flattened, with a little fossa at its base, as in the kero- dons ; the maxillary is connected behind with the temporal, near the glenoid facet, external to the palate bone ; but what distinguishes capybara from them is, that this articulation is much more extensive, and that we cannot see, within, the long pterygoid apophysis and that portion of the palatine alluded to above. The external pterygoid alae are obliterated; the internal alae terminate by a rounded plate, which is very far from reaching as far as the Fig. 259.

Text Appearing After Image: Skull of the Capybara. tympanum. The palatine encroaches upon the palate as far forward as the third molar Fig. 260.

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