138 Prof. H. G. Seeley. On the Nature and Limits [Apr. 26, 



it makes to the Golden Cape Mole, Chrysochloris aurea. Its teeth are 

 rather more numerous in the premolar region, but otherwise the 

 molars in the mammal similarly have one root ; they have the same 

 transverse extension with three cusps, of which the middle one is 

 similarly well-developed, so that the chief differences are that in 

 Chrysochloris the crown is wide on the outer margin and narrows 

 internally as a wedge, while the external cusp is subdivided into two. 

 The lower jaw teeth of Empedias resemble those in the skull, but in 

 Chrysochloris the mandibular teeth are bicuspid, except that the first 

 two molars have the inner cusp divided longitudinally. In the 

 accompanying figures these genera are contrasted ; and if Galesaurus 

 suggests a primitive mammalian type allied in dentition to seals, 

 Empedias as strikingly resembles an insectivorous mammal. 



Fig. 5. 



Empedias molaris. Chrysochloris aurea. 



Reptilian dentition. Mammalian dentition. 



The Lacertilia include many types of dentition, among which are 

 genera with characters suggestively mammalian both in the grouping 

 of the teeth and forms of the crowns. 



In the Frilled Lizard, Chlamydosaurus, there is one canine tooth at 

 each anterior angle of the lower jaw, and these teeth are separated 

 from each other by small incisors. In the skull there are on each 

 side in corresponding positions two canine teeth placed side by side 

 laterally in succession to each other. 



