372 HALITHERIUM. 



molar series, none of them being displaced by vertical successors : 

 in this respect it manifests, like the Dugong, a cetaceous character, 

 and the more strongly, inasmuch as the number of molars succes- 

 sively developed from before backwards is greater. The anterior 

 teeth are, however, displaced before the posterior ones are developed, 

 although they have no vertical successors, which circumstance is also 

 characteristic of the Elephant : the shape, the structure, and the mode 

 of implantation of the molars of the Manatee quite accord with the 

 pachydermal type, and herein more especially with the Dinotherium 

 and Tapir. 



149. Halitherium{\) . — An extinct herbivorous Cetacean has been 

 discovered in the miocene tertiary deposits which resembles the Dugong 

 in many parts of its skeleton, and in having permanent tusks in the 

 upper jaw : but which has complex, ridged, enamelled and many-rooted 

 molars as in the Manatee. The grinding surface of these teeth 

 offers a slight modification of form ; the superior molars when first 

 found detached were referred by Cuvier to the Hippopotamus dubius : 

 the lower molars to the Hippopotamus medius. The latter, PI. 97, 

 fig. 5, have three tuberculate ridges, the posterior one the smallest ; 

 when worn down the crown of the tooth presents three pairs of 

 rounded lobes, and its margins are deeply festooned. The upper 

 molars (fig. 4) are more square-shaped, and the third tubercular ridge 

 is almost obsolete. 



In a second species of the same or a nearly allied genus 

 (Halitherium Brochii) the crowns of the teeth are more rounded, 

 and beset with tuberculated mammiliform eminences. The entire 

 series on the left upper jaw is shown in PL 97, fig. 1, and a similar 

 series of three molars in the left ramus of the lower jaw of the 

 Halitherium Cuvieri (fig. 2). The ultimate discovery and restoration 

 of a great part of the skeleton of one of the species {Halitherium 

 Cuvieri), and the determination of the small number of molar teeth 

 in both species, have established a very interesting intermediate genus 

 between Halicore and Manatus, and, at the same time, one which 

 pushed its infinities much nearer than either of the existing genera 

 towards the pachydermal aquatic genus Hippopotamus. 



(1) Metaxyiherium, Christol, Cheirotherium, Bruno. 



