216 ON THE EXTINCT MAMMALIA OF 



Length of premolar series, .... 



Depth of lower jaw back of last premolar, 



9. Measurements of isolated lower true molars : 



Diameter of last true molars, antero-posteriorly, 

 Diameter of second " " 



Occipital condyle. — An occipital condyle of Titanoilierium, in Dr. Evans' collection, 

 appears less bent than in Bliiivxeros. It measures four inches four lines in its long 

 diameter, and nearly three inches in its short diameter. 



The different collections of fossils, from the Mauvaises Terres of White River, sub- 

 mitted to my examination, contain a large quantity of fragments of huge bones, which 

 appear to be entirely referable to Titanoiherixbm, though most of them are so muti- 

 lated and weather-worn as to have their characteristic markings obliterated. Among 

 the better preserved specimens, corresponding ones diflfer so much in size as to lead 

 to the suspicion that they belong to two different species. The evidence at present 

 appears to me to be insufficient to justify a separation, and I have therefoi'e 

 viewed the fossils as pertaming to different-sized individuals and sexes of a single 

 species. 



An enigmatic specimen, among the fossil bones attributed to Titanoilierium, resem- 

 bles the horn core of the hollow-horned ruminants, nor have I been able to make 

 anything else of it. It is a comparatively short, stout, slightly curved cone, rather 

 more compressed or wider in one direction than the other. The apex is blunt and 

 roughened. The constitution of the specimen strongly resembles that of the horn 

 core of an Ox. The base exhibits a coarser cellular structure, and the largest cell 

 of the specimen was occupied by a crystal of calcite about an inch in diameter. The 

 length of the specimen is six inches ; the breadth within a couple of inches of the 

 broken base is about four inches one way and three inches the other. Should this 

 peculiar specimen really belong to Titanotherium, it would place the animal in nearer 

 relationship with the ruminants than I had suspected. 



Vertehrce. — Of portions of two specimens of the second cervical vertebra, the more 

 perfect measures about five inches in length from the summit of the odontoid process 

 to the posterior margin of the body. Posteriorly the latter is strongly concave. 



An isolated body of a posterior cervical vertebra is short in comparison with its 

 breadth, and is convex anteriorly and concave posteriorly. It measures about two 

 inches in length, and anteriorly about four inches in breadth. The spinal canal, 

 between the roots of the vertebral arch, is two and a half inches in width. Another 

 cervical vertebra has the same length as the preceding, but is less equal in its 



