. On the anatomy of vertebrates [electronic resource] . ical ridge of the maxillary. The interorbitalseptum is perforated behind, beneath the orbitosphenoid. Thereis no distinct lacrymal bone ; but the turbinal bones appear atthe fore part of the orbit between the two processes of themaxillary which join the frontal, and above the aperture com-municating with the nasal cavity. The anterior part of themaxillary, in front of the antorbital foramen, is swollen, andforms a curved canal commencing by an oblique aperture su-periorly, and descending outward and backward round thesocket of the superio
. On the anatomy of vertebrates [electronic resource] . ical ridge of the maxillary. The interorbitalseptum is perforated behind, beneath the orbitosphenoid. Thereis no distinct lacrymal bone ; but the turbinal bones appear atthe fore part of the orbit between the two processes of themaxillary which join the frontal, and above the aperture com-municating with the nasal cavity. The anterior part of themaxillary, in front of the antorbital foramen, is swollen, andforms a curved canal commencing by an oblique aperture su-periorly, and descending outward and backward round thesocket of the superior incisor to terminate in the nasal meatus :this part may probably protect the lacrymal sac and duct. Theinterparietal is a transversely quadrate bone. The sagittal sutureis retained, and the upper surface of the parietal is smooth, andnearly flat: the temporal ridges meet and develope a crest uponthe narrow frontals, obliterating the frontal suture. The backpart of each ramus of the lower jaw is trident-shaped from the 376 ANATOMY OF VERTEBRATES. 242. Skull of the Spalax typhlus. almost equal developement of the coronoid and angular processes,on each side the base of the narrow process supporting thecondyle. In the Great Mole-Rat (Orycteropus capensis), the occipitalregion of the skull is very broad and low. The compressedparoccipitals project downward and backward. The auditorybulla is pyriform, its apex articulating with the pterygoids. The temporal fossae meet alonga well-developed crista ex-tending from the interor-bital region to the strongtransverse superoccipitalcrest. The squamosal formsa horizontal plate, with acurved border extendingfrom the root of the zygomato above the meatus ex-ternus, which is directedupward and forward. Thezygomatic arches are strongly curved outward. The premaxil-laries extend further backward than the nasals: these are verylong and narrow. In the Blind Mole-Rat ( Spalax typhlus), theorbit, fig. 242, o, is not defined: the great antorbital vac
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