1310 



CLASS MAMMALIA. 



Desmotylus. Further information is, however, required before this 

 reference can be definitely accepted. 



Family Halitheriid^e. — The fossil forms constituting the Hali- 

 theriidcE are characterised by the presence of upper incisors ; by the 

 cheek-teeth being coated with enamel, like those of the Manatidce ; 

 and by the retention, in at least some cases, of a milk dentition. 



Fig. 



-Grinding surface of the penultimate and last right lower molars of Halitherium 

 fossile ; from the European Miocene. 



In the type genus Halitherium (which may be taken to include 

 Halianassa, Pugmeodon, and Felsinotherium) there is a pair of tusk- 

 like upper incisors, and either five or six cheek-teeth in each jaw ; 

 small nasals are present in at least some of the species ; the pre- 

 maxillas and mandibular symphysis are bent downwards ; there is a 

 descending plate at the angle of the mandible ; and a small rod-like 

 ossification represents the femur. The molars (fig. 1183) have a 

 pattern on their grinding surface resembling that of Hippopotamus. 



Fig. 1 184. — Skeleton of Halitherium Schinzi ; from the Lower Miocene of Hessen-Darmstadt. 



Much reduced. 1 



This genus ranges from the Lower Miocene (Middle Oligocene) 

 to the Lower Pliocene of Europe ; and remains of H. Schinzi 

 (fig. 1 1 84) are especially abundant in the Lower Miocene sands 

 of certain districts of Hessen - Darmstadt. Prorastomus, from 

 Tertiary strata in the West Indies, is a generalised form apparently 



1 In this figure the deflection of the premaxillse is omitted, 



