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. Bucldand 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. 



