AMPHITHERIUM. 59 
loosened and slightly displaced after decomposition of the 
soft parts; and the anterior teeth, which are missing, were 
probably lost from the same cause, before the jaw was 
finally encased in the oolite. There is a small anterior as 
well as posterior tubercle at the base of the large middle 
cusp or cone, in each of the three premolars which are in 
place: the middle cusp of the posterior one is fractured: 
there is a slight ridge along the inner side of its base in 
that tooth, indicating the transition to the true molar 
series, the commencement of which is indicated by the 
dotted line. The first true molar is wanting; the next 
four present the inner surface of their crowns in a perfect 
and uninjured state: the large middle cusp has a smaller 
one at the anterior and posterior part of its base; this is 
traversed by a strong ridge along the inner side, which 
supports three small cusps; one of these rises at the middle 
of the base of the large external cusp, and the other two 
form the anterior and posterior extremities of the crown of 
the tooth. This form of grinder resembles that of the 
Phascolotherium except in the presence of the middle internal 
cusp, more than that of the molars of the true Didelphys. 
The sharp points of these multicuspid teeth are well 
adapted for crushing the cases of coleopterous insects, and 
correspond essentially, though with a generic modification 
of form, with the teeth of the existing Insectivora, as Bats 
and Shrews. ‘‘ The existence of the wing-covers of Insects 
in the secondary series, in the Oolitic slate of Stonesfield,” 
Dr. Buckland states, “has been long known ; these are all 
Coleopterous, and in the opinion of Mr. Curtis, many of 
them approach most nearly to the Buprestis, a genus now 
most abundant in warm latitudes.”* In the present example 
of the jaw of the small co-existing Insectivores, the con- 
* Bridgewater Treatise, vol. i. p. 411. 
