Dr. J. Murie — On the Sivatherium giganteum. 443 



the inferior base of the skull of ruminant tribes and other Mammalian 

 groups.^ He demonstrated salient characters for classifying, in the 

 foramina and relative disposition and development of the bones. 



The fossilized condition of Sivatherium crania precludes much being 

 drawn from the foramina. The contour of the basal surface of the 

 skull is a most unusual one for a ruminant, the area posterior to 

 the palate and teeth being remarkably broad and quadriform. The 

 length occupied by the teeth is short, and about equal to that posterior 

 to it. This portion of the palate is of moderate breadth ; that 

 anterior to it, comprising portions of the maxillaries, is relatively 

 very narrow. Unfortunately, the fore part of the palate is not pre- 

 served, but I presume it to have been comparatively narrower than 

 what obtains in the ordinary antelopes. In the basi-occipital we 

 have an element for judging the aflinities of the animal. In sheep 

 and goats the bone in question is broadish throughout, and dis- 

 tinguished by what Turner has denoted as anterior and posterior 

 tubercles of the basi-occipital. In the antelopes there is a greater 

 tendency to narrowing forwards of the basi-occiput, but the anterior 

 tubercles are full and prominent. In Cervus the said bones are 

 broader posteriorly, but narrow forwards, which gives them a decided 

 wedge- shape ; the tubercles, fore and aft, are less marked than in 

 the preceding forms ; the posterior tubercles especially almost run- 

 ning, as it were, into the condyles. Nearly the same characters 

 distinguish the oxen, but with this difference, that the median furrow 

 betwixt the tubercles is shallower. 



The basi-occiput of Sivatherium, as far as I can judge from the 

 fossil specimen, may be said to be intermediate between these 

 two families. It is of triangular form, narrow anteriorly, and with 

 very moderate elevations, representing posterior tubercles. The 

 occipital condyles are very large and wide, and so set backwards as 

 in a great measure to hide the foramen magnum when the skull is 

 viewed from below. 



The posterior nares appear rather short and with no great width 

 crosswise. The tympanic bullae are small and, I presume, laterally 

 compressed, but the mastoid and ex-occipital regions have a consider- 

 able breadth, though flat. The glenoid surfaces are very large, and, 

 as Falconer remarks, truly ruminant in character. The result of the 

 characters of the base of the skull with the proviso of a certain amount 

 of obscurity or indefiniteness from deposition of stony matrix, inferen- 

 tially demonstrate the skull's basis as a modification between that of 

 the deer and ox tribe, with tendencies quite as much to the latter as 

 the former. 



5. The Nature of the Teeth. — It has been conjectured on good 

 grounds that the Sivatherium had no upper incisors nor canines. 

 This necessarily excludes it from the ruminant groups possessing 

 these. As to the molar series, these have one attribute peculiar to 

 a limited section of the ruminants, viz., the enamel exhibits rugose 



1 In three communications laid before the Zool. Soc, respectively published in 

 Proc. 1848-9-50. 



