OVIBOS MOSCHATUS. 7 



Ovibos and Bubalus Coffer is the enormous development of the frontal sinuses in the latter, 

 which causes the coronal surfaces to assume the form of a segment of a circle antero-pos- 

 teriorly, while in the former the corresponding surface is but slightly curved. 



The Facial Aspect. — Running transversely across the parietals at a short distance 

 above the orbit, is a stout bony ridge (PI. Ill, i) or step, which is peculiar to the old male 

 Ovibos. The fronto-nasal suture extends nearly at right angles to the median line, instead 

 of being directed obliquely forwards at a very acute angle, as in the Ovis, Capra, Bos, and 

 especially Bubalus Caffer. In the European Bison it runs at a slightly greater angle than 

 in the Bovidse, and then suddenly ends in a right angle with the median line, while in 

 the American it is straight throughout. The nasal bones are much wider posteriorly 

 than anteriorly, and their anterior extremities are much narrower than in the Bovidae, 

 two points in which they approach Ovis and Capra. The premaxillaries are slender, 

 and their sides converge anteriorly, as in the Goats and Sheep, while in Bubalus, Bos, and 

 Gnu, they are nearly parallel. They do not extend, as in Bos, as far back as the nasals, a 

 character which they share with the Bison. They end in a small rounded extremity. 

 The facial plate of the maxillary is much more vertical in Ovibos and Ovis than in Bos, 

 Bubalus, or Bison, and the facial ridge is represented by a stout boss above the root of the 

 first true molar, as in Bubalus Caffer. The lachrymal bone also has a strong ovine cha- 

 racter impressed upon it in the broad deep excavation in front of the orbit. In the female 

 skull in the College of Surgeons it is very shallow, in the two skulls of old males in the 

 same collection very broad and deep. In the majority of the Antelopes, as the Gnu, in 

 common with the Oxen, Bison, and Buffalo, this is absent ; in others, however, as the 

 Bontebock and the Eland, it is also found. 



Orbits. — The outward projection of the orbits differentiates most strongly Ovibos 

 from the true Bovida?, and especially from Bubalus Caffer. In the Bison, however, the 

 same character is found, and is more developed in the European than in the American 

 species. This is a decided ovine affinity. A reference to the table of measurements 

 will give the comparative projection of the orbits in all the mammals quoted in this 

 essay. 



Summary of Head. — In fine, the whole contour of the skull of Ovibos mosc/iatus, in its 

 tapering forwards, in the prominence of its orbits, in the verticality of the facial plate of the 

 maxillary and the lachrymal excavation, prove that the animal is more closely allied to 

 the Sheep than to any other of the Mammalia. The analysis of the different bones of the 

 skull proves that it is separated further from Bubalus Caffer than from the true Oxen or 

 the Bisons. It approaches the Gnu nearer than any of the large cavicorn ruminants, 

 though the following points of difference are found in the latter : the occiput is broader 

 than high, basisphenoid keeled, premaxillary palatal surface spatulate and expanded, 

 premaxillaries articulate with nasals ; thus, although there is a superficial resemblance to 

 Ovibos in this animal, in those points which have been enumerated in the description 

 of the skull of the former, it is overborne by more important differences. 



