| OCR Text |
Show 1900.] STRUCTURE OF THE MUSK-OX. 707 and maxillae is characteristic and wavy, because each palatine has a median and a lateral lobe extending forward on both sides of the foramina palatina (fig. 7). The molar series are a little arcuate and converge anteriorly, so that, for instance, in an adult bull the distance between them is anteriorly 56 and posteriorly 84 mm., measured at the alveolar brim. The length of the molar series in the same specimen is 144 m m . The length of the molar series compared with the basal length of the skull is in a cow 32 per cent. and in a bull 31 per cent, of the latter measurement\ The palate extends well backwards so that the choanae open behind a line connecting the posterior edge of the last molars. This seems to be a difference from the condition of the Caprina as well as that of Fig. 7. Palatal surface of skull of Musk-ox. many Antelopes (Nemorhcedus, Rupicapra, Gazella, Antilope2, Cephalophus, &c). On the other hand, it offers a superficial resemblance to the Bovina. The extension of the masseter muscle in a forward direction over the lateral surface of the maxillary is comparatively short, probablv because it has such a wide area on which it may expand, below the orbital tube (fig. 3, p. 691). As a result of this, the crista 1 This relation between the length of the molar series and the basal length of the head seems to be pretty equal in the ruminants. The following results may be quoted to prove this : in a Buffalo the molar series measured 3 O 0 p. c. of the basal length of the skull, in a common Ox 2 93 p. c, in a Goat 31*1 p. c, in Hemorhadus 323 p. c, in Rupicapra 29'7 p. c, in Gazella 34-1 p. c, in Antilope Bl'O p. c, in Cephalophus 333 p. c, in the Wapiti 32-8 p. c, in the Reindeer 27'9 p. c.; but in Saiga, with its reduced number of teeth, not less than 29 8 p. c, and so on. 2 In the Saiga the choanse open behind the molars, a fact which may stand in relation to the reduced number of molars. |
