LACERTILIA. 



309 



line longitudinal ridges, the terminations of which give the 

 crenate character to the unworn margins of the crown. 



In a portion of the upper maxillary bone of Macellodou 

 Brodiei, the low palatal alveolar plate terminates internally in 

 a smooth border, which had formed the outer boundary of an 

 extended palatal vacuity, as in most lizards ; this structure, 

 with the unequal development, the succession, and pleurodont 

 mode of implantation of the teeth, indicates the Lacertian 

 affinities of Macellodon. 



The remains of small, lizard-like reptiles, with teeth more 

 or less fitted for piercing, cutting, or 

 crushing the chitinOus covering of 

 Articulata, are such as might be ex- 

 pected in the marly shell-beds of the 

 Purbeck series, which have afforded 

 such abundant evidence of insect 

 life ;* and with them are associated 

 remains of small, insectivorous mam- 

 mals (Spalacotlierium). A larger Pur- 

 beck saurian, with teeth adapted to 

 pierce the scales of ganoid fishes, 

 has on that account been referred to 

 a genus called EcliinodonA It re- 

 sembles Macellvdon in the general 

 shape of the teeth, but they have the 

 thecodont implantation. The crown 



presents, however, that leaf, or scale- dj Portion of jaw, nat. size, and 

 shaped type, of which the teeth of teetll > & and c, niagn. of 



t-, 7 /-> 7 • 7 tt 7 Echinodon (Purbeck beds). 



ratceosaurus, (Jardiodon , Hylceosaurus, 



Scelidosmtrus, and even those of Iguanodon, are modifications. 

 The teeth of Echinodon are distinouished from those of 



Fig. 107. 



* See the paper by Mr. Westwood, in the Quarterly Journal of the Geological 

 Society, 1854, p. 378. 



f Echinos, hedgehog; and odous, tooth, "prickly tooth." 



