ROOM III. LOWER JAW OP THE IGUAXODOX. 241 



was involved ; but nearly a quarter of a century passed by 

 ere that privilege was attained. 



Although the specimen I am about to describe does not 

 belong to the national collection, yet it throws so much light 

 on 'the subject under review, and imparts such additional 

 interest to the objects before us, that I feel assured the intel- 

 ligent reader will not consider the following somewhat minute 

 description of the first discovered portion of the lower jaw 

 of the Iguanodon, as irrelevant to the immediate purpose of 

 this volume. 



LOWER JAW OF THE IGUANODOX.' Lign. 53 and 54. In 

 the deltas and estuaries of rivers which flow through coun- 

 tries of varied geological structure, we naturally expect to 

 find the remains of terrestrial vertebrated animals that have 

 been transported by the currents from far distant lands, in a 

 more or less mutilated state ; the skeletons broken up the 

 bones dissevered, fractured, and waterworn the teeth de- 

 tached from the jaws and dispersed and all these separated 

 parts promiscuously imbedded in the mud, silt, and sand of 

 the delta, and intermingled with the debris of the flora of the 

 country, and the remains of fishes, mollusks, and crustaceans, 

 that inhabited the fresh water, or were denizens of the adjacent 

 sea. Such, as we have already pointed out, is the condition 

 in which the bones and teeth of oviparous quadrupeds are 

 found in the Wealden formation, and hence the difficulty of 

 obtaining satisfactory evidence of the form and structure of 

 the extinct reptiles whose relics are so abundant in some of 

 the deposits. 



To this cause may be ascribed the remarkable fact, that 

 although many hundred teeth, belonging to several genera of 

 saurians, have been collected from these fluviatile strata, 

 scarcely a portion of the cranium, and but a few fragments of 

 the jaws, have been discovered. Every relic of this kind is 

 consequently in the highest degree interesting, and it was, 



1 The following account of the maxillary organ of the Iguanodon is 

 an abstract of my Memoir, " On the Structure of the Jaws and Teeth of 

 the Iiruanodon," communicated to the Koyal Society in May, 1848, and 

 published in the " Philosophical Transactions " of the same year. The 

 Koyal Medal of the Society was awarded to the author for that com- 

 munication. 



R 



