Peterson : Miocene Beds of Nebraska and Wyoming. 31 



Greatest transverse diameter of the skuli i°°* II2 



Transverse diameter of the condyles 28 33 



Greatest transverse diameter of brain cast 45 5 2 



Transverse diameter of postglenoid process at base io 16 



Antero-posterior diameter of postglenoid at base 9 



Antero-posterior diameter of tympanic bulla 28 



Transverse diameter of tympanic bulla l6 l 9 



Antero-posterior diameter of the orbit 28 * 



Vertical diameter of the orbit 2 7 



Vertical diameter of jugal below the orbit * 6 *7 



Length of superior dentition 97 



Antero-posterior diameter of P 1 , P^, and P- 4 33 



Antero-posterior diameter of molar series 4° 



Antero-posterior diameter of P- 2 - I2 



Transverse diameter of P^ 



Antero-posterior diameter of M^ 2 ° 



Transverse diameter of M- 3 - *4 



Restoration of Phenacoccelus Typus. 



The type of the genus Phenacoccelus is the basis for the articulated 

 skeleton represented in Fig. 5. The specimen was found in position 

 in a soft sandstone with the left side partly exposed and lost by 

 erosion. The skeleton is mounted very nearly in the same position 

 in which it was found. The parts of the specimen which are preserved 

 are the following : one side of the skull and the angle of the right 

 jaw, all the presacrals and ribs, the pleurapophysis of the first sacral, 

 four of the anterior caudals, the right fore limb complete to the 

 phalanges of the pes, the left scapula, part of the right ilium and 

 ischium, the left hind foot and limb complete to the proximal end 

 of the tibia, which is restored. There is only a short section of the 

 shaft of the left femur. The rest of the skeleton as seen in Fig. 5 is 

 restored in plaster. There are a number of other specimens of the 

 same species in the collection, which might have been used in sup- 

 plying missing parts, but it was thought best not to include in the 

 restoration any other portions than those which had belonged to 

 the type. The vertebral formula is : cervicals seven ; dorsals four- 

 teen ; lumbars six; sacrals?; caudals nine (?). The animal had a 

 rather short and deep head, a short neck, and a large thoracic cavity ; 

 the tail was probably short, judging from the proximal vertebrae, 

 which from the first to the fourth decrease rapidly in size and in the 

 prominence of the different processes. The pelvis is only moderately 



