. Une introduction à l'étude des mammifères vivant et disparu. Les mammifères. HALITHERIID^ 223. et si les liaisons intermédiaires pourrait être découvert pourrait bien être considérée comme la forme ancestrale à partir de laquelle ces derniers ont été tirés, mais à l'heure actuelle, la situation de transition n'ont pas été détecté. Pour autant que nous le sachions, lorsque des changements dans les conditions physiques de la mer européenne lui suffire pour être rendus de la demeure de siréniens, le type Halitherium prévaut toujours. Si les dugongs et lamantins sont descendus de lui, leur évolution doivent avoir eu lieu durant le pliocène et

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. An introduction to the study of mammals living and extinct. Mammals. HALITHERIID^ 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. Halitherium remains have been found in many parts of Germany, especially near Darmstadt, also in France, Italy Belgium, Malta, etc. 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 Fio. 74.—The penultimate and last right lower molars a skull and several ^^ Halitherium fossile; from the Miocene of the Continent. , , , -, , T j_ i T (After De Blainville.) teeth have been detected among the rolled debris of which the Eed 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 f 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.—Eemains from the Pliocene of France des

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