FOSSIL FOOTPRINTS OF THE JURA-TRIAS. 537 



Genus Sustenodactylus nom. nov. (Running to a narrow point.) 



Stenodactylm E. Hitchcock, '58, p. 116 (name preoccupied). 



Generic characters!. Quadrupedal, digitigrade; pentadactyl manus and pes. Digits 

 extremely slender and tapering, without claws or pads. Pes about twice the size of the 

 manus. 



Sustenodactylus curvatus (E. Hitchcock). 

 Stenodactylus curvafiis E. Hitchcock, '58, p- 116, pi. 20, fig. 11 ; pi. 34, fig. 3. 



Sjjecific characters. Pes : divarication of the lateral digits, 70°. Length of digit I, 

 .018 m.; of II, .020 m.; of [II, .026 m.; of IV, .022 m.; of V, .0065 m., vestigial. Length 

 of foot, .026 m. Length of step, .090 m. Width of trackway, .064 m. 



Manus: divarication of lateral digits, 180°. Length of digit I, .006 m.; of II, .007 

 m.; of HI, .013 m.; of IV, .014 m.; of V, .003 m. 



Type specimen, no. ^-|, of the Hitchcock cabinet, from Turner's Falls, Massachusetts. 



Genus Isocampe E. Hitchcock. (Equal curve.) 



Isocampe E. Hitchcock, '58, p. 119. 



Generic characters. Quadrupedal ; manus and pes of unequal size, the former tetra- 

 dactylous, possibly pentadactylous ; the latter tetradactylous. Digits of the pes nearly 

 parallel and curved toward the median line ; those of the manus nearly straight, diver- 

 gent. No pads nor claws. Digitigrade ; with a caudal trace. A short limbed, broad 

 bodied form. 



Isocampe strata E. Hitchcock. 



Isocampe strata E. Hitchcock, '58, p. 120, pi. 20, fig. 5 ; pi. 36, fig. 5. 



Specific characters. Pes: digits parallel. Length of digit I, .042 m.; of II, .051 m.; 

 of III, .058 m.; of IV, .055 m. Length of step, .161 m. Width of trackway, .078 m. 



Manus : divarication of digits I and II, 5° ; of II and III, 5° ; of HI and IV, 25° ; of 

 I and IV, 35°. Length of digit 1, .028 m.; of II, .043 m.; of III, .030 m.; of IV, .028 m. 

 Position of manus a little in advance of, and within the pes impression. 



Type specimens, no. \l, from Turner's Falls, Massachusetts, and no. ^, from Middle- 

 town, Connecticut, both in the Hitchcock cabinet. 



