1900.] STRUCTURE OF THE MUSK-OX. 717 



case in Nemorhcedvs and Haploceros ; but in Ovibos it lies in front 

 of the posterior margin of the symphysis. Rupicapra resembles 

 Ovibos in this respect. 



The hamulus pterygoideus internus is larger, more pointed, and 

 more curved backwards, in Budorcas than in Ovibos. The choanse 

 open in both species behind the molars. This is a difference from 

 Nemorhcedus and Rupicapra. 



The foramen infra orbitale is, in Budorcas as well as in Ovibos, 

 situated rather far back, above the last premolar, but in Nemo- 

 rhcedus above the first or second. Rupicapra and Haploceros 

 resemble the latter. 



The processus postr/lenoideus is smaller in Budorcas than in Ovibos, 

 but the shape of the surface for articulation is similar. 



These characteristics derived from the shape of the facial hones 

 are of comparatively little value, as their possibility of variation is 

 rather considerable. 



The construction of the fronto-parietal region of the skull is, I 

 regret to say, only known to me from the literature of the subject. 



According to the description of Budorcas published by A. Milne- 

 Edwards l , the frontal sinuses do not extend farther than just to 

 the base of the horn-core, and are consequently less developed than 

 in Ovibos. The elevation of the frontals, however, on which 

 the horns of Budorcas are placed, " contient une multitude de 

 grandes cellules en relation indirecte avec les fosses nasales " 

 (op. cit. p. 370). 



Such an arrangement seems to agree very well with the corre- 

 sponding one in the Sheep, but offers no resemblance to the massive 

 exostoses on the head of the Musk-ox. The situation of the 

 parietal in the Takin is also quite different from that of the Musk- 

 ox. In the former this bone " se releve brusquement pour 

 constituer la face posterieure de Ferninence ceratophore." This 

 elevation of the parietal corresponds with the same in the Caprina, 

 and, as in the latter group, this bone seems to be considerably 

 shortened compared with the condition in the Antelopes. The 

 fossa temporalis is in Budorcas, as in the Antelopes in general and 

 in the Caprina, quite open posteriorly and upwards. 



The construction of the upper parts of the skull seems to 

 indicate that the position of Budorcas in the system cannot be 

 so very far from the Ovine branch. I have not had satisfactory 

 material to express any decisive judgment, but I am inclined 

 to think that Budorcas is most likely to be regarded as a 

 primitive Sheep which has become specialized in a certain 

 direction ; but, on the other hand, its affinity to the NemorTicedus 

 group cannot be denied. The resemblance between Budorcas and 

 Ovibos is only superficial Matschie, who lately has taken up this 

 theory, seems 2 to have based it on the following " gemeinsame 

 Merkmahle " : (1) flat and broad metacarpal bones, (2) shape of 



1 ' Keoh. pour servir a l'Hist. Nat. d. Mammiferes,' Paris, 1868-74. 



2 Sitz. d. Ges. Naturf. Fr. Berlin, Jahrg. 1895, p. 31. 



Pboc. Zooi,. Soc— 1900, No. XLV1I. 47 



