aT ra 2 La f 
DIDELPHYsS 4 7A 
MARSUPIALLA ? DIDELPHID&? 
Fig. 22. 
PS, 
is 
Outside, nat. size. Upper view. Inside, nat. size. 
DIDELPH YS? COLCHESTERI, Owen. 
Didelphys Colchesteri. CHARLESWORTH, Mag. Nat. Hist., 1839, p. 450, fig. 60. 
Opossum ? LyxEL1, Annals of Nat. Hist. vol. iv. p. 190. 
Tue fossil above figured in three views, though small 
and not yielding decisive evidence as to its generic rela- 
tions, forms one of the interesting unequivocal evidences 
of the Mammalian class, which the careful researches of 
Mr. Colchester, of Ipswich, have brought to light from the 
Kocene sand underlying the red-crag at Kyson, near W ood- 
bridge, Suffolk. 
It consists of a small portion of the right branch of a 
lower jaw, with one double-rooted premolar tooth and the 
sockets of two others, and it has been referred by Mr. 
Charlesworth,* who first described it, to the Opossum 
genus (Didelphys). He states, “The tooth, in its sym- 
metrical form, united with the indication of an anterior, 
as well as posterior heel or talon, does not agree with any 
species of Didelph with which I have as yet been able 
to compare it, but I think no doubt can be entertained 
of the generic or family affinities indicated by the cha- 
racters which it exhibits. Judging from the empty alveoli 
on either side, the tooth appears to be the one immedi- 
ately succeeding the true molars: its posterior tubercle is 
* Loc. cit. 
