IGTTANODONTmE. 191 



Genekically Undeteemined Specimens. 



The following are from the Wealden of the Isle of Wight. 



39533. A dermal spine. This specimen has not the compressed 

 form characteristic of Polacanthus and Hylceosaurus. 



Presented by E. Backhouse, Esq., 1866. 



R. 202. A shorter dermal spine. Fox Collection. Purchased, 1882. 



R. 202 a. A somewhat shorter dermal spine. Same history, 



36515-17. Three still shorter dermal spines ; from Sandown. 



Mantell Collection. Purchased, 1853. 



R. 133. Two dermal spines of somewhat similar type. 



Fox Collection. 



R. 133 a. Two smaller dermal spines. Same history. 



R. 202. Two dermal scutes. Same history. 



37713-14. Two dermal scutes. Said Collection. Purchased, 1863. 



R. 643. A dermal scute ; from Brook. 



Presented by J. E. Lee, Esq., 1885. 



The following is from the Lower Wealden ( Wadhurst Clay), 

 near Hastings. 



R. 604 a. A tall dermal spine. Dawson Collection. Purchased, 1885. 



The following is from the Neocomian Bone-bed of Potion, Bedfordshire, 

 but is probably derived. 



40458. A water-worn dermal scute. Purchased, 1867. 



Family IGUANODONTID^. 



Cranium (fig. 41) typically somewhat short,, elevated, and broad 

 anteriorly, with small and somewhat prominent orbits, tall infra- 

 temporal fossae, and large terminal nares ; mandibular rami deep, 

 and uniting in a broad and channelled symphysis, terminated by a 

 predentary bone. Teeth (fig. 37) in a single row, with obtuse 

 subtriangular crowns, having (at least usually) serrations on the 

 borders and vertical ridges on the outer surface, and being worn 

 more or less horizontally by use. Cervical vertebrao usually opistho- 

 and dorsals amphiccelous ; anterior and middle dorsals with either 

 tall or low arches, wide neural canal, and deep pits in front of post- 

 zygapophyses ; their centra more or less compressed laterally, and 



