LOXOLOPHODON AND UINTATHERIUM. 21 



post-glenoid processes are longer, the occipital condyles less prominent, canines 

 set wider apart and the canine alveoli more compressed from side to side ; 

 the premaxillaries are shorter, and the horizontal plates between them pro- 

 duced further forwards. The hard palate is produced backwards by the 

 horizontal plate of the palatine bone slightly behind the last molar in L. cornu- 

 tiis, while it is opposite the last molar in L. Speiria?ium. With the exception 

 of the last features, the base of the skull closely resembles that of L. cornutus. 



Comparison with L. galeatus. — The shape of the occiput principally dis- 

 tinguishes this species from L. galeatus. Judging from a figure of the latter 

 which Prof. Cope has kindly lent us, the occiput of L. galeatus w^as about 

 thirteen inches broad and twelve inches high, while the occiput of L. Speirianum 

 is eleven inches broad by thirteen high. 



Skull of Loxolophodon Speirianum. Description in detail, (see Plate I.). 

 The general contour of the head has already been described. The Nasals, which 

 are unusually long, form the upper and all of the anterior portion of the snout, 

 and are produced upwards upon the inside bases of the median protuberances; 

 behind this they pass back beyond the line of the orbits to form a V-shaped 

 suture with the frontals, terminating in a point about half-way between the 

 median and posterior protuberances. The snout, rounded above, narrows 

 gradually. It is not constricted immediately in front of the protuberances 

 as in L. cornuttis, nor does it taper so rapidly as in Uintatheritint. At its 

 extremity it is broad and shovel-shaped, and not so deeply notched as in 

 L. cornutus. The Premaxillaries form the downward projecting tips. They 

 are wholly edentulous, with horizontal palatine plates between them produc- 

 ing the hard palate forwards to within an inch of their extremities. This 

 notch was probably, in the living state, still further produced by a membrane 

 which supported a callous pad, opposing the sharp lower incisors. The pre- 

 maxillaries could not be described as "deeply furcate," as in the case of L. 

 cornutus. Their lines of junction with the nasals above and maxillaries 

 behind are indicated in the plate. The Maxillaries rise well on the sides of 

 the snout anteriorly, contributing all of the outer and upper moieties of the 

 forward protuberances, and forming a considerable portion of the zygomatic 

 arch. They contain the wide alveoli for powerful canines ; these are wanting 

 in our specimen. The alveoli indicate that they were much compressed later- 

 ally. The protuberances are about six inches long, placed upon the sides of 

 the skull, slightly recurved, and with an obliquely placed oval in transverse 

 section. A peculiar feature of the maxillaries is their long suture with the 

 lachrymals and short frontal articulation. Projecting back beneath the malar 

 bones they form the lower anterior third of the zygoma, articulating beneath the 

 orbit with the orbitosphenoids, and on their lower sides forming the greater 



