HALITHERIHDA 223 
and if the intermediate links could be discovered might well be 
looked upon as the ancestral forms from which the latter have been 
derived, but at present the transitional conditions have not been 
detected. So far as is yet known, when changes in the physical 
conditions of the European seas rendered them unfitted to be the 
habitation of Sirenians, the Halitherium type still prevailed. If the 
existing Dugongs and Manatees are descended from it, their evolu- 
tion must have taken place during the Pliocene and Pleistocene 
epochs, the one in seas to the east, the other to the west of the 
African continent, which has long formed a barrier to their inter- 
communication. Halithertum remains have been found in many 
parts of Germany, especially near Darmstadt, also in France, Italy 
Belgium, Malta, ete. 
Until a few years ago 
none were known from 
England, probably owing 
to the absence of beds 
of an age corresponding 
to those in which they 
are found on the Eu- 
ropean continent; but Fic. 74.—The penultimate and last right lower molars 
a skull and several of Halitherium fossile ; fron the Miocene of the Continent. 
teeth have been detected ‘**" Pe Bamvile) 
among the rolled debris of which the Red Crag of Suffolk is partially 
composed. The species are not yet satisfactorily characterised. 
Some of them appear to have attained a larger size than the existing 
Manatee or Dugong. One of these, from the Pliocene of Italy and 
France, having but 4 molar teeth, has been separated generically 
under the name of Felsinotherium by Capellini, by whom it has been 
fully described; but the difference in the number of the teeth 
does not afford sufficient grounds for separation from Halitherium. 
Miosiren of the Belgian Miocene, differs in that the last upper 
molar is the smallest, in place of the largest of the whole series 
of teeth. 
Other forms.—Remains from the Pliocene of France described as 
Prohalicore are regarded as indicating a Sirenian closely allied to 
Halicore ; while a molar from the Tertiary of California has been 
made the type of Desmotylus, which is likewise referred to the 
Halicoride. Dioplotherium, from the Phosphorites of South Carolina, 
has been considered to connect Halicore with Halitherium, but even 
its ordinal position is uncertain. 
A portion of a skull found in the Pliocene of Belgium has been 
described as Crassitherium by Van Beneden ; and some compressed 
teeth, somewhat similar to but larger than those of the Dugong, 
discovered in the Miocene of the department of Lot-et-Garonne, 
France, gave origin to the genus Fytiodus of E. Lartet. Of this 
