320 G. F. Eaton — Characters of Pteranodon. 



By assuming that the first four vertebrae of the sacral series 

 (in the broader sense) are homologues of the lumbars of other 

 groups, the total number of presacral vertebras would appear 

 to be twenty-five. This compares closely with the supposed 

 number of presacrals in the Eusuchia. 



Paleontological Laboratory, 



Yale University Museum, February 29, 1904. 



EXPLANATION OF PLATES. 



Plate XIX. 



Figure 1. — Restoration of Pteranodon longiceps Marsh; prepared from 

 the original fossil bones, by H. Gibb, under the direction of G. F. Eaton, at 

 the Yale University Museum, March, 1904. One twenty-fourth natural size. 



Plate XX. 



Figure 1. — Left orbit an 'c circle of Pteranodon. The arrow 



points to the anterior extremity ~x ri.. head. 



Figure 2. — Seventh cervical vertebra of Pteranodon. 

 Figure 3.— Eighth cervical vertebra of Pteranodon. 

 Figure 4. — Ninth cervical vertebra of Pteranodon. 

 Figure 5. — Ninth dorsal vertebra of Pteranodon. 

 Figure 6. — Tenth dorsal vertebra of Pteranodon. 

 Figure 7. — Eleventh dorsal vertebra of Pteranodon. 

 Figure 8. — Twelfth dorsal vertebra of Pteranodon. 



AIKhe figures are three-fourths natural size, and illustrate the left side of 

 the specimens. 



