THE 



JOURNAL OF GEOLOGY 



JANUARY-FEBRUARY, igo6 



AMERICAN AMPHICCELIAN CROCODILES 



S. W. WILLISTON 

 The University of Chicago 



As long ago as 1849, Sir Richard Owen described' a genus (Hypo- 

 saurus) of amphiccelian crocodiles from the Cretaceous of New Jersey, 

 based upon imperfect anterior dorsal vertebrae, whose chief character- 

 istic was the unusual development of the hypapophyses. But httle has 

 been added to our positive knowledge of the genus since its original 

 description, though the remains of such animals are said to be com- 

 mon in the New Jersey deposits. Leidy, in 1865, described and 

 figured- other vertebrae, and also assigned to the same genus certain 

 fragments of hollow propodial bones. Cope, in 1869, also described^ 

 additional vertebrae and hmb bones, with illustrations, but I think 

 there is much uncertainty as to the correlation of these hmb bones with 

 the vertebrae. He also mentioned certain parts of the skull, from 

 which it would appear that Owen was correct in locating his genus 

 among the longirostres. However, Cope at the same time referred 

 portions of the rostrum of one specimen from the same horizon and 

 same locality as those of the specimens which he referred to Hypo- 

 saurus rogersi Owen, to a distinct species, under the name Hypo- 

 saurus fraterculus, but which he afterward removed^ to the genus 



1 Owen, Quarterly Journal of the Geological Society, Vol. V (1849), p. 383. 



2 Leidy, Cretaceous Reptiles, p. 18, Plate III, Figs. 4, 16-21; Plate IV, Figs. 1-12. 



3 Cope, Extinct Batrachia, etc. (1869), p. 80, Plate IV, Figs. 10, 11. 



4 Cope, Cretaceous Vertebrata (1875), p. 254; Proceedings of the Academy of Nat- 

 ural Sciences, Philadelphia, 1875, p. 19. 

 Vol. XIV, No. I I 



