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THE POPULAR SCIENCE MONTHLY. 



had the habit of a hippopotamus. The femur, or thigh-bone, in a 

 large individual, was about thirty-three inches long, and the humerus 

 nineteen inches. The teeth were flat, and had a serrated cutting edge 

 like the teeth of the iguana ; and hence the name, signifying iguana- 

 like teeth / many of them, from old animals, are worn off short." Le 

 Conte's " Geology " also says that " the animal takes its name from the 

 form of its teeth, which are much like those of the iguana, a living 

 herbivorous reptile, although in other respects there is little aflinity." 

 Figs. 1 and 2 show respectively the tooth of an iguanodon, and a sec- 

 tion of the jaw of the iguana, for comparison. 



Fig. 1. Tooth of an Iguanodon. 



Fig. 2. Section or Jaw of an Iguana. (After Buckland.) 



Le Conte adds : " But the difference in size between the living and 

 the extinct reptile is enormous. The iguana is from four to six feet 

 long ; the iguanodon was certainly thirty feet, perhaps fifty or sixty 

 feet long, and of bulk several times greater than that of an elephant. 

 A thigh-bone has been found fifty-six inches long, twenty-two inches 

 in circumference at the shaft, and forty-two inches at the condyle. 

 Its habits are supposed to have been something like those of a hippo- 

 potamus. Like this animal, it wallowed in the mud, and fed on the 

 rank herbage of marshy grounds." The article " Iguanodon," in the 

 " American Cyclopaedia," in the course of its technical description of 

 the bones of the animal that had been identified, suggests that the 



