Il6o CLASS REPTILIA. 



chanter of the femur, resemble the corresponding elements of 

 Camptosaurus ; and there are likewise four functional digits in the 

 pes, of which the metatarsals are elongated ; while the teeth, which 

 also occur in the hinder half of the premaxilla, are somewhat simpler 

 than those of Iguanodon. In conclusion, we may mention two im- 

 perfectly known forms which are evidently related to this family. 

 Of these, Mochlodon, from the Upper Greensand of Austria, is 

 characterised by the absence of the channelled mandibular sym- 

 physis characteristic of typical forms ; while Craspedodon, from the 

 Upper Cretaceous of Belgium, is a very small Dinosaur, merely 

 known by its teeth, which are more complex than those of 

 Iguanodon. 



Family Scelidosaurid^e. — This family includes a group of re- 

 markable Dinosaurs of medium dimensions, characterised by being 

 clad in a stout dermal armour, usually consisting of detached scutes 

 and long spines, but sometimes taking the form of a solid carapace 

 completely covering the lumbar region. The rami of the mandible 

 are slender and tapering, but it is not known whether a predentary 

 bone was present. The teeth (fig. 1061) have laterally flattened and 

 subtriangular crowns, with the borders carrying serrations set more 

 or less obliquely or parallel to the long axis of the tooth. The 

 anterior and middle dorsal vertebrae differ from those of the 

 Iguanodontidcz in having the articulation for the head of the rib 

 forming a " step " on the transverse process, as in Crocodiles, and 

 not a facet on the arch ; while there is also no fossa between the 

 transverse process and the postzygapophysis. The limb-bones are 

 solid and massive ; the pre- and postacetabular 

 processes of the ilium very long ; and the pubis 

 and ischium comparatively short. The femur 

 has an inner trochanter ; the metatarsals are 

 short and thick ; and the pes, which was probably 

 plantigrade, always has four functional digits. 

 This family connects the Iguanodontidtz with the 

 StegosauridcE, and appears to be confined to the 

 Old World, ranging from the Lias to the Creta- 



Fig. 1061. — Tooth of ceOUS. 

 Scelidosatirus Harri- r 



soni; from the Lower The type genus Scehdosaurus, of which a tooth 

 TwL natu?aT£ hlre * is shown in fig. 1061, occurs in the Lower Lias 

 of Dorsetshire ; and is well characterised by the 

 strongly-marked serrations of the teeth, and the short and conical 

 dermal spines or scutes. In the Wealden, the well-known Hylceo- 

 saurus was a Dinosaur of considerable dimensions, characterised 

 by its enormous and laterally-compressed dermal spines, but of 

 which the skull and teeth are unfortunately still unknown, certain 

 detached teeth which have been provisionally referred to it being 



