THE OSTEOLOGY OF VULPES MACROTIS. 403 



of these ossifications in many of the mammalia. They appear to be of certain 

 taxonomic value among the bats. 



The hyoidean apparatus, in so far as its osseous parts are concerned, is not 

 complete in this skeleton, some of the delicate bones having been lost. There 

 is every indication, however, that it in no way markedly departs from the cor- 

 responding structures in other small foxes, and in the main with the Canidae 

 generally. Professor Flower gives an excellent account of the hyoidean apparatus 

 of the dog in his Osteology, and I have studied these visceral arches in both 

 adult and embryonic types among the mammalia. They are more or less uniform 

 for the family, and among the Canidae, if my information be correct, present 

 hardly any generic differences. The mandible has the general form of that bone 

 in the family Canidae (PI. XXII, figs. 1, 3 and 4), it being V-shaped in form, 

 and ankylosed quite firmly anteriorly by an extensive symphysis. By active 

 maceration, however, the two elongated rami will separate at this point, as has been 

 the case in jaws of the coyote and kit fox at hand. According to some authorities, 

 in very old animals the union may become complete and firm through coossification. 

 In V. velox a ramus of the mandible is shorter, deeper, and thicker through and 

 through than it is in V. macrotis, in which latter fox it is evidently more delicately 

 fashioned. Either ramus has an extreme length of about 7.9 cms., its lower margin 

 being thickened and rounded, convex in the antero-posterior direction, and very 

 slightly curved from side to side. Its upper border exhibits the sockets for the 

 implantation of the mandibular teeth, six much smaller ones occurring anteriorly 

 on the united rami for the incisors. The symphysis has a length of about 2.3 cms., 

 it being more extensive in front and tapering off behind. Between a canine socket 

 and the coronoidal vertical portion of the jaw, the alveolar border is quite straight, 

 while nearly a level surface exists anteriorly and above the symphysis bounded by 

 the sockets of the first premolars, the canines and the incisors. The condyles stand 

 out quite prominently, being transversely elongated, narrow and attached by their 

 mid-anterior points at right angles to the plane of either coronoidal portion of the 

 jaw, at points about half way between the apices of the coronoid processes and the 

 angles, or about in the same plane in which the alveolar borders lie. The coronoid 

 process upon either side is flat and smooth on its mesial surface, and concaved 

 throughout upon its external aspect. It is, on the whole, moderately recurved 

 backward, the true apex being pointed in that direction. Its anterior border, ex- 

 ternally, is thickened and there forms a narrow though conspicuous rim. At either 

 angle there is a prominent angular process developed, which is present in the jaws 

 of all of the Canidae examined by me. Anything approaching a subangular lobe, 

 however, is quite absent, — in which character, strange to say, it agrees with Icticyon 

 venaticus, but not with Otocyon lalandii (where this lobe is much produced), nor 

 with Cam's azarcs and C. littoralis. On the mesial aspect of either ramus below 

 and between the condyle and the posterior commencement of the alveolar border, 

 we meet with the inferior dental foramen, it being of some considerable size, and 

 opens directly backward. 



