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of size, but from a difference of proportion in the measurements of 

 different parts. Thus the Dinornis didiformis differs from the D. gi- 

 ganteus " in its relatively shorter and broader metatarsus." But we 

 cannot enter into the details of this part of the memoir, which would 

 be scarcely intelligible without the splendid plates by which it is illus- 

 trated. Yet it forms the part that must have required the greatest labor 

 and most profound anatomical knowledge, and it constitutes a most 

 instructive and valuable lesson to him who aspires to an acquaintance 

 with the noble science of comparative anatomy. We do not recollect 

 any problem in the " Ossemens Fossiles," that required equal sagacity 

 and skill to solve. 



(3.) This paper throws light on the Ornithichnites, or fossil footmarks 

 of birds in the new red sandstone of this country. — "In 1836," says the 

 author, " Prof. Hitchcock published his remarkable discovery of impres- 

 sions in the new red sandstone of the valley of the river Connecticut, 

 Massachusetts, which he conceived to be the footprints of birds, the largest 

 belonging to a species with three toes, surpassing the Ostrich in size. 

 The epoch of these impressions is as ancient as that of the Cheirotheria 

 or Labyrinthodont footsteps in Europe, and more ancient than those 

 of the oolite and lias, from which the remains of our most extraordinary 

 extinct reptiles have been obtained ; but no fossil bones of birds have 

 been found associated with the Labyrinthodont and Thecodont reptiles, 

 nor with those of the lias or oolites, the Pterodactyles of which were once 

 mistaken for birds. The Wealden is the oldest formation in which true 

 ornitholites have hitherto been discovered. The ancient footprints of 

 the Connecticut sandstones were for the most part supposed to be those 

 of Grallce ; but the high geological antiquity, and the inferences which 

 might be deduced from the low character of the air-breathing animal 

 creation as indicated by fossil bones, of the condition of the atmosphere 

 during the deposition of the oolites, lias, and new red sandstones, led 

 me to express a doubt in my report on British Fossil Reptiles, whether 

 footprints alone were adequate to support the inference, that the ani- 

 mals that impressed them actually possessed the highly developed re- 

 spiratory organization of a bird of flight. One could hardly in fact 

 venture to reconstruct in imagination the stupendous bird, which, on 

 Dr. Hitchcock's hypothesis, must have left the impressions called Or- 

 nithichnites giganleus ; for before 1843, the only described relic of the 

 extinct New Zealand bird did not warrant the supposition of a species 

 larger than the Ostrich." 



44 The species of Dinornis, in fact, to which that relic belonged, we 

 know not to have exceeded seven feet in height, which is the average 

 stature of the Ostrich. But the bones of the Dinornis gigantens, subse- 

 quently acquired, demonstrate the existence at a comparatively recent 



