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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 41. 



considerably smaller. As indicated by a deep depression on the 

 dorsal border, the injury was probably received from above. 



The exostosis of the bone was greatest on the front side of the 

 cavity where it measures 72 mm. in width. The normal width of 

 this part of the ihum, as shown by one on the opposite side, is only 

 21 mm. A second injury was found on one of the caudal vertebrse 

 near. the root of the tail, as indicated by the pathological condition 

 of the spinous process, wliich is considerably enlarged and has near 

 its base an elongated opening which perforates the bone. While the 

 wound in the ilium must have been an exceedingly painful one at the 

 time of infliction, it in no way utterly disabled the animal, at least 

 to the extent of leading to its death, as all of the broken margins of 

 the bone had healed. Although these injuries may have been in- 

 flicted by some of its large carnivorous contemporaries, the position 



Fig. 3.— Right dentary of C.imptosaurus. Internal view showing dentition of lower jaw. 

 About f nat. size, a, anterior end; rf, dent.^ry; p, posterior end. 



of the wounds suggests the idea that this individual was a female 

 who might have received the injuries during copulation. 



The evolutionary history of Camptosaurus is largely unknown. 

 The nearest allied form appears to be Iguanodon, found in Europe, 

 and Prof. O. C. Marsh was among the first to recognize the many 

 similarities in structure between Camptosaurus and Iguanodon. 

 Wldle the former is proportionally much ligliter and more delicately 

 constructed, the habits and mode of life of the two animals must have 

 been very similar. In many particulars, however, Camptosaurus 

 represents a more generalized type, as is shown by the somewhat 

 simpler structure of the teeth, the less reduced pollex and hallux, the 

 postpubis reaching to the end of the ischium, and the more proximal 

 position of the fourth trochanter of the femur. 



