FOSSIL FOOTPinXTS OF TIIK JURA-THIAS. 527 



Tarsodactylus caudatus K. llitelicock. 

 Tarsodactylus miidatm E. Hitclicock. '58. p. '•»'■•, pi- 17. fig. 4; pi. 06. tig. 2. 

 This form approximates Anomoepm minimus closely in size iiiid proportions, being 

 but little larger. It may prove identical. 



Type specimen, no. ^. of the Hitchcock cabinet, on shale from Turner's Falls. Massa- 

 chusetts. 



Tarsodactylus expansus C. II. Hitchcock. 



Tarsodactylus expansus C. H. Hitchcock, '66, p. ■3<»l-3()2. 



Specific characters. Pes: divarication of digits 11 and Ul, 2-5°; of HI and l\\ 50°; 

 of n and IV, 75° to 80°. Length of digit H, .025 m.; of HI, .037 m.; of n', .02S m. 

 Length of hallux claw, .005 m.; distance from foot, .010 m. Distance between lateral 

 tips, .038 m. Length of foot, .043 m. Length of step, .127 to .178 m. Width of track- 

 way, .140 m. 



Manus : divarication of digits I and H, 30° ; of H and HI, 20° ; of III and IV, 25° ; 

 of IV and V, 25° to 30°; of I and V, 100°. Length of digit I, .012 m.; of H, .020 m.; of 

 HI .019 m.; of IV, .015 m.; of V, .0095 m. Distance between lateral tips. .025 m. Cau- 

 dal trace, slight. 



This form differs from T. caudatus in the greater divarication of the toes; in its 

 smaller size ; in its irregular mode of walking as compared with caudatus, and the fact 

 that it does not trail the toes as does the latter. This feature may be entirely due to the 

 animal's gait at the time the impressions were made and hence may be of little impor- 

 tance as a distinction. 



The type specimen is from near Greenfield, Massachusetts, and is preserved in the 

 cabinet of Prof. C. H. Hitchcock, at Dartmouth college, Hanover, New Hampshire. 



Genus Harpedactylus E. Hitchcock. (Sickle toed.) 

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



Generic characters. Quadrupedal, tetradactylous, plantigrade; heel long, digits 

 sometimes curved inward, sickle-like. This genus represents a group of mud tracks, at 

 least two species of which seem referable to Anomoepodoid forms, wliile the third, //. 

 crassiis, is not so typical. The entire group seems to be of doul)tful validity. 



Harpedactylus tenuissimus K. Hitchcock. 



Harpedactylus temiissimus E. Hitchcock, •45b, p. 24. 



Harpedactylus gracilis E. Hitchcock, '58, p. 112, pi. 20, fig. 4 ; pi. 52, fig. 5. 



