Intergradation was noted in still other cranial details. In the heavy, relatively straight zygomatic arches, a majority of the skulls resemble those of _planirostris_, although some show the elongated zygomatic processes of the squamosals that are characteristic of _virgineus_. Some skulls show a tendency toward _birdseyei_ in the widely spreading posterior regions of the zygomatic arches. The nasals for the most part are as in _planirostris_. Intergradation between all three subspecies is shown in the extension of the premaxillae posterior to the nasals. Some skulls show the lateral concavity of the jugals which is characteristic of _virgineus_. The tympanic bullae are variable but on the average are intermediate between those of _planirostris_ and _birdseyei_, but more as in the latter. The size of the pterygoid hamulae is like that of _planirostris_, but the shape of the interpterygoid space is more like that of _birdseyei_. The size of the molariform teeth is as in _birdseyei_. The incisors are intermediate between those of _planirostris_ and _birdseyei_, but more like those of _birdseyei_. Eighteen specimens from St. George and its environs, on the north side of the Virgin River, agree with the twenty-six specimens just described, except that they show more evidence of intergradation with _birdseyei_ in slightly darker color, length of hind foot, length of nasals and alveolar length of the upper molar series. One specimen from three miles south, two from two miles southwest, another from four miles southeast of St. George, and four immature animals from Short Creek Road south of the town of Virgin, all on the south side of the Virgin River, are darker than topotypes of _planirostris_ and show intergradation with _trumbullensis_ to the south. In size they are likewise closer to the latter race. They intergrade with _trumbullensis_ in the size and shape of the zygomatic arches and tympanic bullae. In the majority of cranial details, however, they are like _planirostris_ to which they are here referred. One specimen, a skin only, from Danish Ranch, 5 miles northwest of Leeds, north of the Virgin River is an intergrade in size and color between _birdseyei_ and _planirostris_, but referable to the latter. Three specimens from the East Entrance, and three from near the east entrance to Zion National Park are much darker than topotypes of _planirostris_. All of these animals are in worn pelage, thus allowing a great amount of the black underfur to show, which gives a markedly darker color. The unworn hair is only slightly darker than that of the topotypes. The cranial details prove these animals to be intergrades between _planirostris_ and _trumbullensis_. They resemble _trumbullensis_ in size of tympanic bullae, extension of the premaxillae posterior to the nasals and shape of the nasals. The majority of the cranial details are as in _planirostris_ to which they are here referred.