PALEONTOLOGY. 405 



REPTILES. 



Megadactylus Owen. 



Megadactylus polyzelus E. Hitchcock, jr. 



1858. "Bonesof a reptile." Jeffries Wyman. Ichnology of New England, j). 180. 

 1863. Megadactylus polyzelus. E. Hitcbcock, jr. Supplement to Ic^Iinology of 



New England, p. 39. 

 1871. Me(j<i(lnctylu.s polyzelus. E. D. Cope. Synoi)sis of the extinct IJeptilia and 



Aves of the United States: Trans. Am. Phil. Soc., Vol. IV, p. 122a, 



PI. XIIL 

 1884. AmpJiismirus (Megadactylus). O. C. Marsh. Am. Jour. Sci. Sup. XXVII, 



p. 338. 

 1889. Anchisaurus. O. C. Marsh. Am. Jour. Sci. Sup. XXXVII, p. 331. 



This rare and remarkable fossil has had a peculiar history. The bones 

 were thrown out by a blast in excavating a well for the casting of a big gun 

 at the water shops of the United States Armory, in the south part of Spring- 

 field, and only a part of the skeleton was preserved and presented to Presi- 

 dent Hitchcock. These bones were first studied by Jeffi-ies Wyman, and 

 determined by him to be those of a reptile. His letter contains many acute 

 observations. He notes the hollowness of the bones, a peculiarity suggest- 

 ing lairds and pterodactyls, but decides against the reference of the bones 

 to either of these. The unequal length of the toes suggests a jumping 

 animal. 



The bones were then earned to London by Dr. Edward Hitchcock and 

 submitted to Prof. Richard Owen, who determined them to be those of a 

 Saurian reptile, but added otherwise nothing to the diagnosis of Wyman. 

 His one sentence concerning the l)ones is interesting. Thev belong to "a 

 Saurian reptile with an unusually thin wall of bone in the limb bones, 

 which, however, might have been occupied by unossified cartilage, as in 

 the 3'oung crocodile and turtle; but if they were filled with oil or light 

 marrow, it would point to a course of development toward pterodactyls or 

 birds. The jihrase is purely hypothetical, and I mean to express no more 

 than a degi-ee of resemblance, supposing marrow and not gristle to have 

 filled the large cavities." Later, Dr. Hitchcock worked out the bones with 

 a graver and named the animal in the article quoted. 



The specimen was then carefully studied, figm-ed, and described by 



