68 AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



Order URODELA (?) 

 Family LYSOROPHID/E Williston. 



Williston, LysoTOpkida, Biological Bull., vol. xv, 1908, p. 237. 

 Brolli, Paterosanrida, Paleontographica, Bd. Li, 1904, s. 99. 

 Broili, PatiTOsauridcE, Anat. Anzeig., Bd. xxv, 1904, s. 585. 



Original description: Broili founded this family on "the character of 

 the vertebrae, the lack of intercentra, and the presence of jugular plates." 



Williston showed that while the form was properly placed in a new 

 family, the name was given in opposition to the accepted rules of nomen- 

 clature and that it should properly be named Lysorophidce. 



Revised description: The family is regarded as an amphibian in oppo- 

 sition to Broili's contention that it is a reptile, for reasons given in the 

 morphological discussion (p. 141). 



1. Small, snake-like, limbless. 



2. Skull triangular, without temporal fenestrse or parietal foramen. 



3. Anterior nares on outer edge of skull, nearly terminal. 



4. Orbit lateral, without lower borders. 



5. Quadrate inclined forward, bringing articular surface beneath 



the posterior edge of the orbit. 



6. Teeth small and conical. None enlarged. 



7. Lower jaw two-thirds of the length of the skull. 



8. Limbs and girdles absent. 



9. Neural arch free from centrum and divided into lateral halves. 



Genus LYSOROPHUS Cope. 



Lysorophus tricarinatus Cope. 



Cope, Proc. Am. Phil. Soc, vol. xvii, 1877, p. 187. 



Case, Journ. Geol., vol. viii, 1901. p. 714; Journ. Geol., vol. x, 1902, p. 256; Bull. 



Am. Mus. Nat. Hist., vol. xxiv, 1908, p. 531. 

 Broili, Paleontographica, Bd. li. 1904, s. 94; Anat. Anzeig., Bd. xxv, 1904, s. 585; 



Anat. Anzeig., Bd. xxxiii, 1908, s. 290. 

 Williston, Biol. Bull., vol. xv, 1908, p. 229. 



Type: A few vertebrae, No. 6526 University of Chicago, badly broken. 



Paratypes: Nos. 6527, 6528 University of Chicago. Vermilion County, 

 Illinois. 



Original description: "Vertebrae amphicoelian, perforated by the fora- 

 men chordae dorsalis. Neural arch freely articulated to the centrum. Floor 

 of neural canal deeply excavated. No processes or costal articulations 

 on the centrum, which is excavated by longitudinal fossae. Centrum not 

 shortened. 



"Specific characters: Two centra and a portion of a third represent this 

 species. The former are a little longer than wide and a little depressed. 

 The facet for the neural arch is an elongate plane truncating the border of 

 the fossa of the neural canal on each side, for one-half to three-fifths the 

 length of the centrum. Two deep longitudinal fossae extend on each side 

 of a median rib of the inferior face; and they are separated above by a nar- 

 rower rib from another longitudinal fossa which is below the base of the 

 neural arch. 



