526 RICHARD SWANN LULL ON 



III and IV, 65°; of 1 and IV, 180°. Length of digit 1, .013 m.; of 11, .014 m.; of III, .020 

 m.; of IV, .015 m. Length of foot, .022 m. Width of foot, .032 m. Length of step, 

 .076 m. Width of trackway, .076 m. 



Hitchcock considers this form a batrachian because of the similarity to Proteus in 

 number of toes and absence of claws. He also likens the form of the toes to that of the 

 toes of tlie lizard, Anolis. The bipedal walk would seem to associate the form with 

 the Reptilia though it hardly agrees with our conception of a dinosaur. 



Type, no. ||, of the Hitchcock cabinet, on gray shale from Turner's Falls, 

 Massachusetts. 



Forms occasionally quadrupedal. 



Genus Xiphopeza E. Hitchcock. (Sword foot.) 



Xiphopeza E. Hitchcock. '48. p. 239. 



fTCiieric characters. Quadrupedal, possibly not habitually so ; plantigrade ; the tetra- 

 dactylous pes much larger than the manus which, in the known specimens, impresses but 

 three digits. 



Xiphopeza triplex E. Hitchcock. 



Xiphojiezn triplex E. Hitchcock. '48, p. 239, pi. 15. fig. 8; '58, p. 113. pi. 20. fig. 6; 

 pi. 52, figs. 3. 4. 6. 



Specific characters. Pes: divarication of digits I and II. 90°; of II and III, 40°; of 

 III and IV, 50°. Length of digit I, .013 m.; of II, .020 m.; of III, .038 m.; of IV, .028 

 m.; of the heel. .030 m. Length of foot, .066 m. Distance between lateral tips. .038 m. 

 Breadth of heel, .012 m. Length of step, .102 m. Width of trackway, .115 m. 



Manus: but three digits impressing, aJiout .010 m. in length. 



Type specimen, no. ||, of the Hitchcock cabinet, on gray shale from Turner's Falls, 

 Massachusetts. 



Genus Tarsodactylus E. Hitchcock. (Toed tarsus.) 



Tarsodactylus E. Hitchcock. '58. p. 98. 



Generic characters. Quadrupedal, digitigrade; manus pentadactylous, pes tetra- 

 dactylous with broad digits and somewhat acuminate claws but without phalangeal pads. 

 Tail trace present. A very rare group. 



