68 BibUograpMcal Notices. 



The third type of this group is the new species Trilophodon 

 Palconeri. The tooth differs from those of M.jmndionis in its smooth 

 enamel, low vertical ridges, wide transverse valley, and trefoU- 

 shaped dentine islets. 



Part 2 opens with a statement of the author's conviction that 

 the Indian species of DinotJierium must be maintained, and are not 

 to be identified with the European type. 



Dr. Falconer's divisions of the genus Hippopotamus, named Hexa- 

 protodon and Tetraprotodon, are here united, and Leidy's genus CJice- 

 ropsis is included with them in the genus Hippopotamus. Some 

 account is given of crania of Hippopotamus siualensis, in which the 

 molar teeth vary in proportions ; and the author finds that a large 

 series of vertebrae and limb-bones show distinctions from Hippopo- 

 tamus ampliibius. The spinous process of the axis is higher, the odon- 

 toid process blunter ; the scapula has its long diameter shorter ; 

 the femur apparently includes two types ; the astragalus is longer 

 than in H. ampliibius and approximates to the pigs, 



A small hippopotamus from Burma, named by Falconer and 

 Cautley Hexaprotodon iravaticus, is distinguished from H. sivalensis 

 by the shorter symphysis and the greatly diminished interval be- 

 tween the canines, in which characters it makes a nearer approach 

 to the pigs than any other hippopotamus. The species H. nama- 

 diciis was referred to by Falconer as larger than H. amphibius or 

 H. sivalensis. It has only been obtained from the JS'arbadas, and 

 the author observes that the crania referred by Falconer to H. palce- 

 indicus might with equal reason be referred to H. namadicus, and 

 describes a mandible. H. p>al(jeindicus presents a singular type of 

 mandible, the jaw being that of a Hexaprotodon in process of con- 

 version into a Tetraprotodon, the middle incisors being forced 

 inwards and greatly reduced in size by the development of the fii'st 

 and third incisors. The H. iravaticus is the most generalized Indian 

 species, and steps of successive modification are exhibited by the 

 species H. sivalensis, H. namadicus, and H. palceindicus, at least as 

 shown in the increased shortening of the symphysis of the mandible. 

 H. amphibius in length of symphysis rather exceeds the Narbada 

 hippopotamus, its inner incisors are large and the outer incisors 

 small ; but in H. liberiensis the small outer incisor has disappeared. 

 The representatives of swine among the Siwalik rocks are referred 

 to the genera Sus, Hippohyus, Sanitherium, and Hyotherium. An 

 interesting summary of modifications of the genus Sus precedes the 

 description of Indian species. Sus giganteus of Falconer and Cautley 

 is described from specimens of crania, dentition, and mandible, so as 

 to show its difierences from S. scrofa, S. cristatus, S. barbatus. The 

 third and fourth premolars of this species are wider and stouter 

 than the corresponding teeth of most existing pigs ; but the struc- 

 ture is similar to that of the premolars of Tetraconodon. Sus titan is 

 a new species founded on mandible, cranium, teeth, and limb-bones, 

 and is regarded as distinct from S. giganteus. The first and second 

 molars are of narrower and more elongated type than in that species; 

 but whether it is distinct from the Eiiropean types may admit of 



