Reptilian Bird from the Trias of Massachusetts. 301 



XXXIII. — Description of a new Reptilian Bied from the 

 Trias of Massachusetts. 



By C. H. Hitchcock. 

 Read April 9, 1866. 



Foe original description of the genus Tarsodactylns see Ich- 

 nology of New England, by Edward Hitchcock, 1858. 



Tarsodactylns expansus. 



Hind Foot. — Tetradactylous, three of the toes pointing forward : 

 pachydactylous ; hind toe reaching the ground only with its extremity 

 on the inner side of the heel, or near the roots of the front toes. Hence 

 it must have been inserted high upon the tarso-metatarsus. Divari- 

 cation of the lateral toes 75 o -80° ; of the inner and middle 25° ; of the 

 middle and outer 50° ; of the axis of the foot with the line of direction, 

 the foot turned inward, 20°-25°. Distance between the rows of right 

 and left tracks two to three inches. Length of the inner front toe one 

 inch; of the middle, 1.43 inch; of the outer, 1.1 inch; of the claw, 

 0.12 inch. From tip to tip of the lateral toes, 1.5 inch ; between the 

 inner and middle, 0.75 inch ; between the middle and outer, 1.2 inch. 

 Projection of the middle toe beyond the rest 0.62 inch. Length of the 

 foot, 1.7 inch ; length of step by alternate hind feet, 2 to 4£ inches; by 

 the right or left feet, 5 to 7 inches. Middle toe barely trails in one 

 instance. Track ornithoid. Width of trackway 5.5 inches. Length of 

 impression made by fourth toe 0.2 inch, about 0.4 inch distant from the 

 foot, and on the inside. 



Fore Foot. — Pentedactylous, pachydactylous ; turned outward on the 

 right hand side, forward on the left hand side. This irregularity is per- 

 haps due to a curve in the line of the animal's progress. Divarication of 

 the lateral toes, 100° ; of the inner and second, 30° ; of the second and 

 third, 20° ; of the third and fourth, 25° ; of the fourth and fifth, or outer, 

 25°-30°. Length of the outer toe from the middle of the posterior 

 part of the foot, 0.37 inch ; of the fourth toe, 0.6 inch ; of the third, 

 0.75 inch; of the second, 0.8 inch ; of the inner toe, 0.48 inch. From 

 tip to tip of outer toes, 1 inch. Width of toes, 0.2 inch. Foot repti- 

 lian. There is one slight caudal marking in the middle of the track- 

 way, indicating the possession of a long slender tail. 



