FOSSIL FOOTPRINTS OF THE .TITRA-TRIAS. 



48/ 



Generic characters. Bipedal,' tetradactylous ; hallux rotated to the rear so as to lie in 

 line with the claw ol' the second digit, insistent, that is, inserted high on the leg so that 

 only tile tip of the claw impresses and that only when the weight is borne on the hinder 

 part of the foot. The hallux evidently bore a well developed, subfunctional, grasping 

 claw. Foot of moderate size with well marked phalangeal pads. Limbs of medium 

 length. Manus and tail never impressing. 



This genus is clearly correlated with the Anchisaurus and Ammosaurus of Marsh and 

 is here separated from Hitchcock's genus Eubrontes (Brontozoum) the latter being 

 retained for the larger herbivorous forms which were grouped with the carnivorous 

 species. 



The type species is Anchisaurijins dananus (Brontozouni sinimanium, in part, of the 

 Ichnology) the track of Anchisaurus column Marsh. 



Anchisauripus dananus (E. Hitchcock). 



Eubrontes dananus E. Hitchcock, '45b. p. 2o (in part). 

 Brontozoum sillimanium E. Hitchcock, '47, p. 49 ; '58, p. 

 68, pi. 12, fig. 3 ; pi. 33, fig. 4-5 ; pi. 43, fig. 6, (in part) . 



Specific characters. Divarication of digits I and H, 139° ; 

 of H and HI, 11°; of HI and IV, 18°. Length of digit I, .050 

 m. ; of 11, .077 m.; of HI, .115 m.; of IV, .088 m. Length of 

 foot, not including the hallux, .153 m. ; with the hallux. 

 .187 ni. Distance between lateral tips, .067 m. Length of 

 step, from .300 to .560 m. Width of trackway, .115 m. 



The type specimen is no. ^, of the Hitchcock cabinet ; 

 reddish flagging stone fi'om Middletown, Connecticut. Figured 

 in F. A. Lucas, :01, figure 7. 



This 18 undoubtedly the track of Anchisaurus colurus 

 Marsh ('96, p. 148, pi. 2, fig. 1-3 ; pi. 3, fig. 1-2) from the 

 exact way in which the bones fit the track (fig. 4) . 



This is an extremely common and variable species, the 

 variations consisting in size, complexity of heel pads, breadth 

 and divarication of toes, and the shape of the claws. E. 

 Hitchcock ('58, p. 69) in speaking of this form says: "I have 

 foiuid it chfficult to define the limits of tliis species and I 

 apprehend that as now given it embraces at least two species. 

 But I have failed to seize upon any distinctive characters between them." It seems to 



1 /. 



Fig. 4. Anchisauripus daiiaiius 

 E. Hitchcock. Impre&s of the left 

 pe.s. X 2- From the type, no. J",-, of 

 the Hitchcock cabinet. The skele- 

 ton is based upon that of Anchisan- 

 rus colurus Mar.sh. 



