536 RICHARD SWANN LULL ON 



Orthodactylus linearis K. Hitchcock. 

 Orfhoddcfiihis I'means E. Hitelicock, '58, p. 115, pi. 20, fig. !l ; pi. 48, fig. 4. 



Specific characters. Pes : digits nearly parallel, the divergence of the lateral ones 

 being not over 20°. Digits ranging in length from .007 to .018 m. Length of step, .043 

 m. Width of trackway, .038 m. 



Manus : apparently similar to the pes though much slenderer. 



This species is much smaller and more slender than the others of its genus. The 

 fact of its dragging tail and feet in the type specimen is probably only accidental and not 

 a specific habit. 



The type is no. f|, of the Hitchcock cabinet, on red shale from Turner's Falls, Massa- 

 chusetts. 



Genus Antipus E. Hitchcock. (Opposite foot.) 



Antijjus E. Hitchcock, '58, p. 115. 



Generic characters. Quadrupedal, digitigrade. Pes tetradactylous, manus pentadac- 

 tylous, without claw or phalangeal impressions. 



This genus is named from the pecuUar position of the tracks on the slal), those of 

 the manus and pes pointing in nearly opposite directions. This is probably due to the 

 fact that the lasting impression was made in a particular stage in the creature's walk 

 which was evidently similar to the sprawling gait of the lizards and turtles. The tracks, 

 aside from their position, resemble most closely those of the genus Sustenodactylus. 



Antipus flexiloquus E. Hitchcock. 

 Antipus Jlexiloqw I. ^ E. Hitchcock, '58, p. 115, pi. 20, fig. 10. 



Specific characters. Pes : divarication of lateral digits, 60°. Length of digit I (the 

 outermost as the impression lies), .018 m.; of II, .020 m.; of HI, .020 m.; of IV, .019 m. 

 Length of foot, .029 m. Distance between lateral tips, .025 m. Length of step, .038 to 

 .084 m. Width of trackway, .127 m. 



Manus : divarication of lateral digits, 131°. Length of hand, .023 m.; breadth, 

 .021 m. 



The type is no. g^, of the Hitchcock cabinet, from Turner's Falls, Massachusetts. 



Antipus bifidus E. Hitchcock. 

 Antipus hifichis E. Hitchcock, '58, p. 116, pi. 36, fig. 8; pi. 48, fig. 10. 

 This is an extremely doubtful species. 



