528 



BRITISH FOSSIL REPTILES. 



Fig. 1. 



such serrations. That would be the sole modification needed to make them specifically as 

 well as generically the teeth of Jguanodoii Mcuitelli. 



Of the above-described mandibular fossil Mr. Fox writes: — "This jaw was found 

 within a yard of the skull. They were both in a mass of mud that had slided down 

 from the cliff, and was being gradually washed away by the sea." 



What is wanting in the exposed portions of the tooth-germs in the above specimen, 

 viz. the continuation of the marginal serrations, of smaller size, upon the ridge bending 

 from the margin at the broadest part of the crown upon the inner surface of the 



narrowing basal part of the crown, is fortu- 

 nately supplied by an almost entire lower molar 

 oi Iguanodon Foxii (PI. 60, figs. 12 — 17), which 

 came from a slab of Wealden stone containing 

 a portion of a right mandibular ramus (AV^oodcut, 

 fig. 1), with the symphysis, «, confined to the 

 lower border of the sloping end (as at 5', fig. 1, 

 PI. 59) ; also a few ribs, a caudal vertebra of the pattern of those figured in PL 7 {Din.), 

 and also " a distal phalanx of one of the toes." " I cannot tell," writes Mr. Fox, " where 

 I have the bone itself, but its shape is exactly like that in Iguanodon Mantelli, very little 

 curved in a downward direction, and rather broad.^ In the little paper box, along with 

 the fragment of jaw, you will find one very small tooth, quite perfect," that came out of 

 this slab in dressing."" This slab was found in the fallen cliff, 

 about 150 yards east of " Barnes' High," directly fronting the den 

 of my Polacantlms, which I dare say you will remember seeing. 

 The skull and broken jaw were found about CO yards further 

 eastward."* 



In the accompanying Woodcut, fig. 2, of the caudal vertebra, 

 nat. size, of Iguanodon Foxii, are added letters of reference corre- 

 sponding with those on the figure of a caudal vertebra of Igim- 

 nodon Mantelli (PI. 14, fig. 1). The anterior or cervical vertebrae 

 show the modification of the front ball and hind cup (PL 6, 

 figs. 3, 4). If the sacral vertebrae should show the broad under 

 surface, as in « 4, PL 8, a corresponding variability of vertebral 

 shape in the same skeleton will characterise the present small kind of Iguanodon as it 

 does the large kind. 



The tooth (PL 60, fig. 12) is 5 lines in length in a straight line ; it is moderately curved, 

 with the convexity (as the teeth in situ above described show) towards the inner surface of 



•1 The shape and proportions of the ungual phalanges vary in the toes of the fore and hind feet in 

 Iguanodon Mantelli. 



2 Letter received 4th February, 1870. ^ lb. ib. 



* Letter above cited. Tlie skull and broken jaw are the subjects of figs. 9 and 9 a, of PI. L 



Fig. 2. 



