M. Marcel de Serres on the Skeleton of Metaxytherium. 173 
ately a flash of light was seen at a considerable depth, and 
this the sailors assured me was from the shoal of herrings. 
If this was phosphoric light emitted by these finny wanderers, 
then is this phosphorescent quality possessed by zoophytes, 
Meduse, Mollusca tunicata, and fishes. D. L. 
Notice on the Discovery of a complete Skeleton of Metaxythe- 
rium. By M. Manrcet bE Serres. 
Tue genus Metaxytherium has recently been established by 
M. Christol, on various fragments of bone belonging to a ma- 
rine mammiferous animal, which appears intermediate between 
the Lamantin and Dugong. Under the latter name we have 
described the numerous remains of the cetaceous animal we 
met with in the upper marine tertiary sands in the neighbour- 
hood of Montpellier. These fragments consist chiefly of the 
bones of the head, there being a great many of the jaw-bones 
armed with teeth ; the next in quantity are vertebree and the 
bones of the limbs. Since that time, M. Christol has found 
various bones of the same animal in the inferior marine depo- 
sits of the departments of Charente and Maine-et-Loire. 
Availing himself of all the separate pieces, which he has 
compared with singular skill, he has found materials to consti- 
tute his genus Metarytherium, in which he has united the two 
species of hippopotamus described by Cuvier under the names 
of Hippopotamus medius and dubius. We need not be sur- 
prised that even such a skilful anatomist as Cuvier was de- 
ceived by the teeth of this marine mammifer, and that he sup- 
posed it to be of terrestrial habits. In fact, the molars when 
worn down, assume the en ¢refle appearance which character- 
izes the grinders of the hippopotamus to such a degree, that 
when they are not seen planted in the jaw, it would be easy to 
make the same mistake, if at the same time one’s attention 
was not directed to the form and arrangement of their roots. 
And it is not a little singular that this observation did not 
escape Cuvier, which proves that the teeth referred by Peron 
to the hippopotamus really belonged to the Dugong.* 
The genus Metaxytherium, of which we possess the princi- 
pal pieces entering into the skeleton, makes a near approach 
~* Recherches sur les Ossemens fossiles de G. Cuvier, t. v., first part, p. 261. 
