REPTILES ALLIED TO H A DR S AURTJS. 99 



position, and is rather transversely reniform in outline. It exhibits a medullary 

 cavity, occupied by a hard, ash-colored matrix, four inches and a half in transverse, 

 and two inches and three-fourths in antero-posterior diameter, \pith walls of compact 

 ossific substance from one to two inches and a quarter in thickness. The fragment 

 at its narrowest point is seven inches wide, four inches and a half thick at the 

 middle, five inches internally, and three inches and three-fourths externally. 



A second of the fragments, above indicated, appears to be part of the inner side 

 of the shaft of the femur just below the head, and measures nearly four inches in 

 thickness. A third fragment appears to be from the inner side of the lower part 

 of the shaft of the opposite thigh bone. 



Several fragments of large bones, from the Green-sand of Monmouth County, 

 New Jersey, were presented by Dr. J. H. Slack. One of the specimens appears to 

 be from the middle of the shaft of the femur, but of this I am not certain, for 

 what I take to be the inner half of the surface is so deeply eroded (apparently from 

 the action of water to which it had been a long time exposed, while the other half 

 was protected by the mud in which it lay imbedded at the bottom of the ocean) that 

 its characteristic features are to a considerable extent lost. The fragment, about a 

 foot and a half long, had the same quadrate form, and about the same size as the 

 corresponding portion of the femur of Hadrosaurus. Its exposed medullary cavity, 

 emptied of loose green sand with which it was filled, has a diameter of about three 

 inches transversely, and two inches and a quarter antero-posteriorly, with the walls 

 averaging an inch and a quarter thick. 



Of the other firagments, presented by Dr. Slack, two belonged to the lower part 

 of a fibula of the same form as that of Hadrosaurus, but considerably larger. 



A specimen of a metatarsal bone, from Monmouth County, New Jersey, presented 

 by Mr. Isaac M. Hopper, of Freehold, is represented in Figs. 7, 8, Plate XV. It 

 is larger than either of those of Hadrosaurus above described, and also difi'ers 

 from them in form, though it exhibits sufiicient likeness to one of them to lead to 

 the opinion that it belonged to the same enormous Saurian. The proximal end has 

 the same form as that of the metatarsal of Hadrosaurus, represented in Figs. 1, 8, 

 Plate XIV. The distal extremity is less thick and has not such prominent condyles. 

 The shaft is thicker, and its inner surface, instead of being narrowed from the 

 extremities into a median prominence, forms a wide irregular plane. The measure- 

 ments of the specimen are as follows : — 



Inches. Lines. 



Extreme length .... 13 6 



Breadth of shaft at middle . 3 



Depth of shaft at middle 2 3 



Depth of tarsal extremity internally, about ..... 5 6 



Breadth of tarsal extremity at middle 3 3 



Height of phalangeal extremity, from a level, about .... 3 8 



Breadth of phalangeal extremity . 4 



Another metatarsal bone, with its extremities mutUated, from Peale's Museum, 

 formerly existing in Philadelphia, and probably obtained from the Green-sand of 

 New Jersey, was presented by Dr. P. B. Goddard. It appears to have had the 

 same form as the specimen just described, but was somewhat larger. The breadth 



