FOSSIL FOOTPRINTS OF THE .riTRA-TRTAS. 523 



Sillimanius gracilior E. Hitchcock. 



Sillimaidus gracilior Vj. Hitchcock, '45b, p. 24. 



Ornithojjvs r/rnr!Jlor E. Hitchcock. '48, p. 193, pi. 8, fig. 2 ; '58. p. H8. pi. 14, fig. 11 ; 

 pi. 58, fig. 7. 



Specific characters. Pes: divarication of digits I and II, S5° ; of II and III, 35°; of 

 111 and IV, 52°. Length of digit I, .010 ni. (impression) ; of II, .021 ni.; of III, .032 ni.; 

 of IV, .023 \\\. Distance between lateral tips, .043 m. Length of foot impression, .043 

 m. Length of step, .153 m. Width of trackway, .115 ni. Foot digitigrade, entire length 

 of the hallux not impressing. 



The type specimen is no. •^, of the Hitchcock cabinet, on red shale from Weathers- 

 field, Connecticut. 



Oenus Steropoid.es E. Hitchcock. (Like Sterojnis, a Cyclo)is.) 



Steropoides E. Hitchcock, '45b, p. 24. 



Sterojiezoimi E. Hitchcock, '48, p. 182. 



Trident'qjes E. Hitchcock, '58, p. 88 (to replace Steropezoum) . 



Generic characters. Bipedal, tetradactyl, subdigitigrade to semiplautigrade. Tarsus 

 sloping upward so that the impression often ends in ridge.s and furrows. The hallux is 

 rotated backward so as to be in line with digit IV. 



The members of this genus are very similar to those of Sillimanius especially to S. 

 tetradacti/Ins E. Hitchcock. Steropoide>> eJcr/an.'i may be taken as the type. 



Steropoides elegans E. Hitchcock. 



Steropoides elegans E. Hitchcock, '45b, p- 24. 

 Steropoides elegantior E. Hitchcock, '45b, p. 24. 

 Steropezoum elegans E. Hitchcock, '48. p. 183, pi. 5, fig. 2. 

 Steropezoum elegantius E. Hitchcock, '48, p. 184, pi. 5, fig. 3. 



Tridentip)es elegans E. Hitchcock, '58, p. 00, pi. 15, fig. 2 ; pi. 45, fig. G ; pi. 52, figs. 

 8,11. 



Specific characters. Pes: divarication of digits I and 11. 75°; of II and III, 05°; of 

 III and IV, 65°; of II and IV, 125°. Length of digit 1, .040 m.; of II, .040 m.; of HI, 

 .071 m.; of IV, .(I5(i m. Distance between lateral tips, .089 m. Length of heel impres- 

 sion, .064 m. Widtli of heel, .013 m. Length of foot, .135 m. Length of step, .250 to 

 .500 m. Width of trackway, .178 m. 



