76 MARSUPIALIA. 
with due precaution, by means of a fine graving tool, and 
soon brought into view the anterior brim of the pelvis, with 
the two supernumerary or marsupial bones (/ig. 23, a, a,) 
in their natural position, and having the precise form and 
proportions of those of the Opossums.* 
He thus demonstrated that there had been entombed 
in the gypsum of Paris an animal whose genus at the 
present day is exclusively proper to America. 
Well might Cuvier exclaim, when the delicate but clear 
outlines of the parts he sought became manifest, ‘“‘ Que ces ” 
linéamens sont précieux !” and as richly did he merit, as 
he must have enjoyed, the satisfaction of thus stamping, 
in the presence of his colleagues, his principle of palzeon- 
tological research with the impress of its prophetic power. 
* The reader is referred to the original memoir in the “ Annales du Muséum,” 
t. v. p. 277, for the more minute comparisons, establishing the generic relations 
and specific differences of the extinct Didelphys of the Parisian Eocene rocks. 
Fig. 23. 
DIDELPHYS GYPSORUM. 
