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THE POPULAR SCIENCE MONTHLY. 



and perceived that the feathers corresponded with that named by Von 

 Meyer. It seems to differ in only two particulars from ordinary birds : 

 first, there are two fore-fingers, like hooks, projecting from the wings ; 

 and, secondly, the tail is shaped like that of the squirrel, with twenty 

 vertebrae ranged in a line, each with a pair of quill-feathers attached. 

 These variations are not sufficiently great to render it necessary to re- 

 move the Archeopteryx from the bird division, but they indicate in 



Fig. 2. 



Akcheotteetx. 



what direction we are to expect a modification of the ornithic type, as 

 it approaches the reptile. And it is in precisely these two respects 

 that the Triassic Herpetoids differ from true birds. 



The second liuk was furnished by the structure of the feet and the 

 ichnites of the Iguanodon in England. Both pairs of limbs were ter- 

 minated by three-toed feet, often of great size. Only two impressions 

 appear, yet Prof. Owen supposes the tracks of the fore-feet were al- 

 ways covered by the hind-feet. The largest of these impressions are 

 28 inches long and 25 broad, and the stride sometimes reaches 46 

 inches. This was the largest of all the English terrestrial herbivorous 

 reptiles, and his impressions have been extensively collected near 

 Hastings. 



The third link was furnished by the Hadrosaurus of New Jersey, 

 the American representative of the Iguanodon. He appears to have 

 had the general form of the kangaroo, enormous hind-limbs, termi- 

 nated by trifid feet ; a powerful tail, almost rudimentary anterior ex- 

 tremities, with a skull slightly ornithic, the height of the structure 

 being from 12 to 15 feet. It is singularly like the Ichnozoa Gigan- 

 titherium. In fact, if we may follow the fashionable creed of the day, 

 it may be said that the ISTew-Jersey Hadrosaurus was the lineal de- 

 scendant of the Massachusetts Gigantitherium. 



For other links of this series it is only necessary to refer to the 

 late publications of Cope, Huxley, Seely, Owen, Marsh, and other dis- 

 tinguished paleontologists, in which are described nearly a score of 



