56 THE WASATCH AND BRIDGER FAUN^. 



This species differs from some of those of the Bridger formation in 

 the smoothness of the scales on the anterior part of the body. It is a 

 smaller species than most of those of both that formation and the Wasatch. 

 The characteristic vertebrie are e.xhibited by various specimens. 



HALECOMORPHL 



PAPPICHTHYS Cope. 



Annual Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 634. 



Family Ami'uJce. Vertebrae short, the abdominal with prominent dia- 

 pophyses, and with each neurapophysis articulating with two centi'a; sides 

 of the centrum not pitted. Maxillary bone supporting a single series of 

 teeth and with a supplementary bone on its distal upper border. Dentary 

 bone deeply grooved on the inner side and with but one series of teeth. 

 Surface of cranial bones sculptured. 



This genus differs from the existing Amia in the presence of only one 

 series of teeth instead of several, on the bones about the mouth. The ver- 

 tebral centra possess a smaller anteroposterior diameter and relatively 

 greater transverse diameter in the anterior part of the column ; but the 

 value of these characters is not yet certainly understood. 



The maxillary bone overlaps the premaxillary extensively by its proxi- 

 mal extremity, and presents no condylar facets (P. pUcatus). The sym- 

 physis of the dentaries is not sutural. The condyle of the inferior quadrate 

 is rough (P. leevis, P.plicatus). Its posterior grooves show the position of a 

 symplectic ; while the inferior anterior portion shows a coarse sutural ser- 

 rate junction with the ectopterygoid (in the above species). The centra of 

 the vertebrae are most transverse anteriorly; in the posterior abdominal 

 region they become subround; in the anterior caudal region, higher than 

 wide; and in the greater part of the notocaudal region are subround They 

 all have a minute notochordal performation. The neurapophysial facets of 

 the anterior and posterior positions are distinct in the anterior abdominal ver- 

 tebrae, and confluent on the caudals of all the species; the point at which 

 they become confluent is different in the different species. On a few ante- 

 rior abdominal centra the inferior surface is entire, or displays a slight 

 depression; soon two parallel fissures, one on each side of the median line, 



