. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. RODENTIA. 377 ring, it occupies a considerable space in the orbital cavity; but the entrance of the lachrymal canal is concealed by the sub-orbital arch. The bones of the nose are singularly robust; the ascending ramus of the intermaxillary is, on the contrary, very narrow, even at the point where it joins the frontal. The pre- orbital ring is of large size, and the malar apophysis of the maxillary arises close to the intermaxillary suture. A few lines behind the incisor teeth the palatine interposes itself, under the sh
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. RODENTIA. 377 ring, it occupies a considerable space in the orbital cavity; but the entrance of the lachrymal canal is concealed by the sub-orbital arch. The bones of the nose are singularly robust; the ascending ramus of the intermaxillary is, on the contrary, very narrow, even at the point where it joins the frontal. The pre- orbital ring is of large size, and the malar apophysis of the maxillary arises close to the intermaxillary suture. A few lines behind the incisor teeth the palatine interposes itself, under the shape of a round shield-like plate, between the sphenoid and the maxillary. In the echimys the jugal is very long, and tolerably broad ; the lachrymal is small, and is furnished with a little hook-like process ; the maxillary presents, inferiorly, in front of the molar teeth, a small fossa and a malar apo- physis, the margin of which is broad and flattened. The bony arch of the pre-orbital ring is simple, and not doubled posteriorly by an ascending apophysis of the jugal, as is the case in the jerboa ; or by the latter and the lachry- mal, as in the helamys and the viscache. The palatine is deeply indented posteriorly, but it ascends into the orbit, and likewise appears in the pterygoid ala, between the sphenoid and the maxillary. The external pterygoid alae do not extend transversely beneath the foramen ovale. The capromys very nearly resembles the preceding genus in the construction of its face, but in it the jugal bone is broader, and almost rhomboidal in its shape. The sphe- noid also is in contact with the maxillary, above the point of union between this bone and the pterygoid portion of the palatine. Fig. Skull of the Porcupine (Hystrlx cristata). In the common porcupine (Hystrix cristata, Lin.), the bones of the nose are very large and broad, the suture connecting them with the frontal mounts much higher up than the inter- maxillary sutures. The intermaxillary bones
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