Structure of the Fossil Saurians. 291 



Monitors, Turtles, and Birds, is strengthened by a ring of 

 bony plates, and reminds us of the enormous eye of the Ichthy- 

 osaurus. The teeth are flat, pointed, somewhat bent, edged 

 before and behind, and these edges are finely serrated. In the 

 upper jaw, there are at least 17 such teeth in each row. In 

 the vertebrae, the posterior surface is concave, and the trans- 

 verse processes are large. The pelvis nearly resembles that 

 of the Rhacheosaurus, but differs from it in the form of the 

 single bones. The species found in the state of Solenhofen 

 I name, from its discoverer, G. Sommerringii. Are the remains 

 found in New Jersey different from these ? , 



Macrospo'ndylus. 

 With the animal which I have named the Aeolodon, Baron 

 Cuvier classes the remains of a totally different animal. Dr. 

 Jaeger describes it as the Crocodilus bollensis. I have 

 investigated these remains with partly the same assistance 

 which Cuvier and Jaeger possessed, and find them neither 

 referable to the Aeolodon nor to the Crocodiles. The bones 

 of the leg are only in a small degree shorter than the femur ; 

 the vertebrae are longer and smaller, and their posterior surface 

 is concave. No other portion of the skeleton is extant. From 

 the form of the vertebrae, I name the creature to which they 

 belonged Macrospondylus. I have furnished more complete 

 details of this fossil Saurian in the Acts of the Academy of 

 Leopold and Caroline. 



Mastodonsau'rus Jaeger. 

 Dr. Jaeger describes teeth of a conical form, with longitu- 

 dinal striae, beginning at a certain distance from the point, and 

 not penetrating deep. Of these teeth the one measures 

 46J W . long, and 17iJ • • broad at the base. Other teeth, of the 

 same species, are smaller. These teeth have probably only 

 adhered to the inner upper surface of the alveolar process. 

 The animal to which these teeth belonged Jaeger named the 

 Mastodonsaurus. Some bones have since been discovered, 

 which may, probably, be referred also to this animal; but they 

 have not yet been described. I name the animal to which 

 the large teeth belonged, after its discoverer, M. Jaegeri. 



Lepjdosau'rus ? 

 I discovered, in the year 1829, together with the Rhacheo- 

 saurus, scales which were so large and considerable, that they 

 probably belonged to the skin of a large Saurian. Any 

 farther disquisitions, however, concerning this animal, must 

 remain uncertain, till bones have been found together with 

 such scales, since it is possible that they may have belonged 



