400 THE OSTEOLOGY OF VULPES MACROTIS. 



is comparatively large and broad, with its internal and external surfaces quite 

 smooth. For the most part it lies in the vertical plane, being perpendicular to the 

 basi-cranial plane. 



Vulpes macrolis possesses a, very large foramen magnum, a trifle larger in 

 proportion than it is in V. velox, and very distinctly so in comparison with that 

 foramen in C. latrans. For example, the transverse or major axis of the subellip- 

 tical foramen magnum in V. macrotis measures 1.3 centimeters, its minor vertical 

 axis 1.1 cm. and the mid-longitudinal axis of the skull, from the border of the 

 foramen magnum to the most anterior point between the premaxillaries, measures 

 10.2 cms. In C. latrans the corresponding measurements are 1.8 x 1.4 cms., and 

 18.5 cms. The occipital condyles have their narrow and mesial moieties in the 

 horizontal plane where they are bat barely separated in the middle line. Their 

 broader and more rounded halves curl upward, one upon either hand, and their 

 anterior borders are markedly concaved, being correspondingly convex behind. 



As in the Canidae generally the paroccipital processes are conspicuously 

 developed. Either one, as a strong projection, descends and completely molds 

 itself upon the superior and posterior aspect of the corresponding auditory bulla, 

 lending to it considerable support. Between either par-occipital process and the 

 occipital condyle of the same side, there is a narrow though deep valley, while to 

 the outer side of the process, upon this aspect of the skull, may distinctly be seen 

 the mastoid portion of the periotic bone. It is bounded in front by the low, thin, 

 sharp line of the lambdoid or occipital crest. 



Turning to the lateral aspect of the skull in V. macrotis, Plate XXII, fig. 1, 

 the long, narrow face that this fox possesses at once becomes apparent. The 

 lengthy and acute backward projecting naso-maxillary process of the premaxillary 

 is distinctly seen, as is the sutural line between the maxillary and frontal and malar 

 bones. It is tangent to the periphery of the orbit in front, and passes beneath it, 

 below. Forward of this, and above the diastema existing between the third pre- 

 molar and sectorial teeth, is the large and vertical slit4ike infraorbital foramen, 

 for the passage of the second division of the fifth nerve. Within the orbit may be 

 seen the usual foramina and the usual bones forming its smooth, shallow, antero- 

 mesial concavity. The upper half of this is formed by the orbital portion of the 

 frontal; anteriorly by the small lacrymal ; below by the pterygoid and maxillary; 

 externally by the malar ; and postero-mesially by the palatine, orbito-spenoid and 

 the alisphenoid. The various foramina require no special description, as they 

 make no particular departure from those openings as they occur in the skull of the 

 common dog. A description of the zygomatic arch has already been given in a 

 previous paragraph. 



In Vulpes macrotis the meatus auditorius externus, is somewhat larger, in 

 comparison, than in V. velox ; very much more so than in C. latrans. Indeed, 

 the opening is so large in the specimen at hand that the interior of the tympanic 

 cavity can easily be studied from without. The ossicula auditus {malleus, incus 

 and stapes) all appear to be lost, and so cannot at this writing be described. 



