626 BRITISH FOSSIL REPTILES. 



teeth of Iffuanodon, HylaEomurus, or Mcyalosaurus. A happy accident may one day 

 bring to light the connection of the subjects of the present subsection with those of the 

 foregoing of which the dental characters are unknown. 



In this state of doubt it is convenient to indicate the new fossil by a distinct 

 generic term, and such has been suggested, for the subjects of figs. 2 — 5 of Plate 85, by 

 the heart-shaped form of the crown of the fossil tooth. The crown, being 1 inch in 

 length, 8 lines in breadth, and 5 lines in thickness, might well have come, according to 

 the proportions of the teeth of Hylaosaiirus (Plate 39), and Scelidosaurus (Plate 40), 

 from a Dinosaur with trunk-vertebrse of the size of those of species of Chondrosteosaurus. 



In the teeth of Cardiodon the ' crown ' suddenly expands above the ' neck,' and thins 

 off to the fore and hind borders (Plate 85, fig. 3), and contracts to a subacute apex (ib., 

 fig. 2). The enamel rises into wavy longitudinal ridges with widish intervals, where it is 

 minutely rugous. The fang is cylindrical, coated with smooth cement. 



The original or typical specimens of Cardiodon rugidosus were from the ' forest 

 marble ' of Wiltshire.* 



* See my ' Odontography,' 4to, p. 291, pi. Ixxv a. 



