44 Mammalia. Artiodactyla. 



the Diapophysis in length in all the posterior dorsals : no Anapophy- 

 ses are developed. In the eighth Lumlar vertebra the Diapophyses 

 suddenly acquire great breadth, and gradually increase in length to 

 the last lumbar. The first three Sacral vertebrae articulate with the 

 ilia. 



The Liml Bones. There are no Clavicles. The Intercondyloid 

 part of the Humerus is perforated (as in the Tapir). The Fore Foot 

 is unsymmetrically tetradactyle : the Hind Foot has only three toes. 



X. AUTIODACTYLA. 



The Shull. If the species be horned, the Horns form one pair or 

 two pair; they are never developed singly, of symmetrical form, 

 from the median line. The JVasals are usually long and conspicuous, 

 and do not expand posteriorly. The Zachrymal is very large, 

 especially in its facial part. The Super-orhital canals are large in 

 most species. The FrcB-tnaxillaries generally reach to, or are con- 

 tiguous with, the Nasals. The Post-tympanic does not project 

 downward distinctly from the Mastoid, nor supersede it ; and the 

 Par-occipital always exceeds both these processes in length. The 

 Bony Palate usually extends further back than in the Perissodactyles : 

 the hinder aperture of the Nasal passages being more vertical, and 

 commencing posterior to the last molar tooth. The base of the 

 Pterygoid process is not perforated by the ectocarotid artery. 



Omnivora. The orbit is seldom complete : the prccmaxillaries reach the 

 nasals : the malar rarely reaches the frontal : the temporal fossa; are deep and 

 approximate on the top of the cranium : the zygomatic arch is strong : the arti- 

 cular condyle of the jaw is larger than in Euminantia. In Hippopotamus the 

 rim of the orbit is almost, sometimes quite, complete : the lateral series of molar 

 alveoH slightly diverge anteriorly : the basi-occipital forms no part of the occi- 

 pital condyles : each ramus has an antroverted angular process. Most of the 

 uidceh.a.ye apraenasal bone. 



Rurninantia. Processes are generally found on the frontal bone for horn core. 

 The parietals are frequently anchylosed together : the malar and frontal bones 

 generally complete the orbit. The articular condyle of the jaw is small, and 

 plays freely in all directions in a shallow glenoid cavity : the coronoid processes 

 are narrow, and the base of the ascending ramus expanded. The temporal fosses 

 are small : the zygomatic arch weak : the pramaxillaries generally edentulous. 

 The Jffyoid avch. includes long, compressed, hammer-shaped 'stylohyals' attached 

 to short epi- and cerato-hyals : the thyro-hyals are also small ; the basi-hyals 

 normal. [In Camelus no processes are developed from the frontal bone for horns : 

 the^Zygomatic arches, in relation to the laniariform teeth, are long and over- 

 span a wider temporal fossa than in the true Euminantia : the Prsemaxillaries do 

 not reach the nasals : the orbital plate of the Lachrymal shows two perforations : 



