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THE IGUANODON 
Horn ofthelguanodon. Among the recent genera 
of lizards, the Iguanas are distinguished by their 
exuberant dormal appendages ; many of the species 
have enormous serrated processes on the back; others 
on the tail and guttural pouch ; while some have 
warts or horny protuberances on the head ; these, 
however, are so small, the horn in the most favoured 
species, the /. cornuta (vide wood-cut, p, 325.), 
being scarcely a quarter of an inch high in an 
animal 5 feet long, that no one could have imagined 
that the corresponding process of an extinct rep- 
tile would have been preserved through countless 
ages, and submitted to our examination. Such, 
liowever, is the case ; like the claw-bone, it was 
discovered imbedded in the conglomerate of Til- 
gate Forest. This relic is of so extraordinary 
a nature, that although it has been noticed in my 
former work, I am anxious to be permitted to 
dwell on it in this place, that I may introduce the 
remarks of M. Cuvier, by whom it was examined 
during his last visit to London, and at whose sug- 
gestion a more accurate representation has been 
made than that published in the fossils of Tilgate 
Forest. (Vide PI. III. fig. 5.) This horn is of a 
conical form, moderately compressed laterally, and 
slightly recurved ; its surface is corrugated by the 
integument by which it was covered : it is 4 inches 
high ; but as the apex is broken off, it must have 
been at least half an inch higher when entire, thus 
exceeding by eighteen times the magnitude of the 
horn of the recent animal. The base is of an irre- 
gular elliptical form, and sliglitly concave ; its 
