THE OSTEOLOGY OF VULPES MACROTIS. 399 



The zygomatic arches are prominently developed in these animals, and possess 

 the same general characteristics in both species. Their extremities, composed of 

 the usual bones, face directly upward, or, in other words, they have a superior and 

 an inferior surface, the zygomatic or squamosal end being triangular and small, 

 while the malar-maxillary extremity is also triangular, but broad and extensive. 

 The middle third of the arch possesses an internal and external surface, the superior 

 and inferior margins being somewhat sharp and curved, — the upper one convex 

 and the lower concave, Plate XXII, fig. 1. 



In Vulpes macrotis the fangs or roots of the last molar tooth (m 2 ) upon either 

 side perforate anteriorly the zygomatic arch. These perforations occur just within 

 the postero-mesial borders of the expanded portion, there formed by the maxillary 

 bone, Plate XXII, fig. 7. Similarly perforations also occur in Vulpes velox and in 

 C. latrans. Viewing the skull directly from above, the post-orbital processes shut 

 these molar foramina out of sight in the majority of skulls, but they are sometimes 

 seen upon this aspect in macrotis, because it has such a narrow skull and flaring 

 zygomatic arches. 



As in the Canidge generally, either nasal is a long, narrow bone, which, with 

 the fellow of the opposite side, extends from a point opposite the anterior margin 

 of the orbit to the supero-mesial boundary of the anterior nares. Here the border 

 of either bone is notched and free, the two together completing about a fourth of 

 the narial aperature. In Cam's latrans their anterior extremities are truncated 

 from their antero-external angles backward obliquely to their postero-mesial angles. 

 Their hinder ends in Vulpes macrotis articulate with the frontals and are likewise 

 truncated, the two bones together forming a wedge, entering between the -frontals, 

 its apex being situated posteriorly. The external border of a nasal articulates with 

 the corresponding borders of the frontal, maxillary and premaxillary of the same 

 side. In this situation the nasal process of the frontal tends to extend forward to 

 have its anterior apex meet the apex of the nasal process of the premaxillary. 



Between these two species, however, a greater or less interval occurs, greater 

 in velox than in macrotis, while in some of the Canidce (as figured by Huxley) they 

 seem actually to meet. It is certainly the case in Cam's littoralis, and may occur 

 in Cam's vulpes. Foxes and other forms in the family with shorter faces may have 

 the apices of these processes w r ell apart. There is a very considerable interval, 

 for example, in Octocyon lalandii. Upon the posterior aspect of the skull of Vulpes 

 macrotis it is to be observed that in the median line above is the well-developed 

 inter-parietal bone, with its contracted anterior angulation extending forward 

 between the parietals, with its similar and lateral projections lying, on either hand, 

 between the corresponding parietal and supraoccipital. Its mid-Ion gituclinal line is 

 co-extensive with the comparatively feebly developed sagittal crest; the low but 

 well-defined occipital crest traverses from side to side its lateral projections. The 

 parietal sutures of the interparietal long remain visible or even ununited, while the 

 bone seems to early ankylose with the supraoccipital. This is also the case in other 

 Canidse and in many domesticated dogs. As in all true foxes the supraoccipital 



