2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.73 



its study is begun. Those details of structure so essential for reach- 

 ing a satisfactory decision as to affinities and relationships are largely 

 wanting, and for that reason its classification within the order 

 Reptilia remains much in doubt. However, it seems to represent an 

 undescribed genus and species for which the name Hypsognathus 

 fenneri is proposed, the specific name being in honor of Mr. Herbert 

 R. Fenner, who found the type specimen. The illustrations were 

 made by Mr. Sydney Prentice, draughtsman of the Carnegie Museum^ 

 Pittsburgh. 



DESCRIPTION OF SPECIMEN 



HYPSOGNATHUS, new genus 



The characters of this genus are included in the following descrip- 

 tion of the type and only species: 



HYPSOGNATHUS FENNERI, new species 



Type. — Cat. No. 11,643, U.S.N.M. Consists of bone impressions 

 of much of the axial skeleton anterior to the pelvic region. 



Type locality. — Clifton, Passaic County, New Jersey. 



Geological horizon. — Brunswick shale, Upper Triassic. 



When received the specimen was imbedded in a single block of 

 sandstone, the ventral side downward (see pi. 1) and, with the ex- 

 ception of some disarrangement of the neck vertebrae, the remaining 

 parts of the axial skeleton more or less articulated. The posterior 

 vertebral column, from a point in front of the sacrum, is missing, 

 having been inclosed in another slab of rock which was not recovered. 

 Likewise, the skull and upper parts of the vertebrae and ribs were 

 held in the block of sandstone that split off the top of the specimeo 

 and for which unsuccessful search was made by Mr. Fenner. The 

 lower jaws occupy their proper relative position in front of the verte- 

 bral column, and the ribs of both right and left sides are spread out 

 in sequential order on either side of the line of vertebrae. Of the 

 appendicular skeleton only the proximal end of a humerus and por- 

 tions of one foot are recognized ; the latter, from its position in rela- 

 tion to the skeleton is regarded as being the left manus. 



Unfortunately, the soft chalky nature of the fossil bone did not 

 permit developing the skeleton along the usual lines by freeing it 

 from the matrix, and it was only after some experimentation that it 

 was decided to remove the bones so as to leave their natural molds 

 in the rock. (PI. 2.) 



Casts were then made of these impressions, thus securing accu- 

 rate replicas of many of the actual bones. For purposes of study 

 and description these casts were found to serve almost as well 

 as the originals. 



