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THE AMERICAN MUSEUM JOURNAL 



delicate skeleton of a swift-running 

 type of dinosaur, with long, slender 

 limbs, a very long tail, a hand provided 

 with long, very slender fingers termi- 

 nating in sharply recurved claws, a 

 small, delicately formed head with 

 pointed, recurved teeth. 



On its arrival at the Museum this 

 skeleton was very carefully studied by 

 the present writer, who reached the 

 conclusion that this little dinosaur was 



same family of swift runners as the 

 supposed "bird robber," although it 

 cannot be regarded as a direct descend- 

 ant. The first remains of this more 

 recent animal, one of the most extraor- 

 dinary dinosaurs ever discovered, were 

 found near Denver, Colorado, in 1889, 

 and came into the hands of Professor 

 0. C. Marsh, of Yale University, for de- 

 scription. This specimen consisted of 

 the bones of the hind foot, which were 



This complete skeleton of the "ostrich mimic" dinosaur, Struthiomimus (of much more recent geologic 

 age than Ornitholestes) , was discovered by an American Museum expedition in 1914. after a search pro- 

 longed through a dozen years in the Upper Cretaceous dinosaur fields of northern Montana and southern 

 Alberta. Only parts of skeletons had been found previously, and the skull and fore limb had never been 

 seen. Study of these threw an entirely new light on the life habits of this type of dinosaur, and made un- 

 tenable the old theory regarding the bird-robbing propensities of Ornitholestes. The skeleton was brought 

 from Alberta to New York in the solid block of sandstone in which it had lain embedded through the ages 



a carnivore and preyed upon the primi- 

 tive contemporary birds, in which the 

 powers of flight were only partially de- 

 veloped, and the animal was conse- 

 quently given the name Ornitholestes, 

 "the bird robber." The theory was that 

 by great speed and very alert move- 

 ments Ornitholestes was able to over- 

 take and capture its prey. 



It is an interesting instance of how 

 one discovery in science affects another 

 that this theory of the habits of the 

 ancient "bird robber" has become un- 

 tenable through the subsequent discov- 

 ery of another dinosaur, of much more 

 recent geologic age, belonging to the 



placed in a manner so closely similar to 

 that in some of the large existing birds, 

 such as the ostriches and rheas, that the 

 animal received the very appropriate 

 name Ornithomimus, "the bird mimic." 

 In fact, the foot so closely resembles 

 that of a bird that if it had been found 

 in a period before dinosaurs were 

 known to science, it would certainly 

 have been described as belonging to an 

 ancient type of bird. 



Little more was known of this type 

 of dinosaur until 1902 when a collec- 

 tion of limb bones belonging to similar 

 forms was secured through explora- 

 tions along the banks of the Belly Eiver, 



