Oct. 1go1. THE Fore Lec or Morosaurus—RIGGs. 277 
mentary attachment. Phalanx 2 is similar in form but smaller and 
less roughened. The ungual is wanting. Metacarpal III is repre- 
sented by its distal third only. Metacarpal IV has a constricted prox- 
imal end and is more slender in the shaft than Metacarpal V. The 
latter has a conspicuous process for ligamentary attachment on the 
posterior angle of its proximal end. A doubtful phalanx, identical in 
structure with that placed upon Digit [in Am. Mus. No. 332 (loc. cit.) 
has been provisionally referred to Digit V. Its rounded distal end 
with no trace of articulating surface indicates that it was surmounted 
by a cartilaginous pad. The phalanges belonging to Digits III and 
IV have been lost, so that their formula can not be determined from 
this specimen. The gradation’in size of the metacarpals from I to IV 
as well as the mesial inclination of the distal axes of I and II offers 
further evidence that Marsh was right in placing the larger unguals 
on the first digits in this genus. 
An incomplete foot (Pl. XLI, Fig. 2), found by the writer in 
position, confirms the structure of Digit I. This specimen belongs 
to a smaller and more slender species than the last described and in 
the metacarpal region is very similar to the American Museum speci- 
men before cited. The carpals and metacarpals were preserved in 
their normal positions with Digit I complete and closely connected. 
The first phalanges of Digits II and III were also in position; those 
of IV and V were exposed and had been displaced. In this speci- 
men, as in Mus. No. 6668, Digit I is the strongest of the series and 
is armed with a stout claw. Phalanx 1 of this digit has the same 
angular form common to this bone in both the front ahd hind feet of 
Sauropoda. Its close articulation with the carpal by a well-marked 
concave surface, together with the stout ungual which it bears, indi- 
cates the important function laid upon this digit. The digit as a 
whole was directed inward and forward, showing no indication of 
having been opposable, as in the larger form. 
The metacarpals grade evenly in size from the first to the fourth; 
the fifth is about as strong as the second. In length there is a notice- 
able tendency toward symmetry in the series. The first and fifth are 
nearly equal, as are the second and third; the fourth is intermediate. 
On the postero-lateral angle of Metacarpal II there is a strong pro- 
cess for ligamentary attachment. The first phalanges of Digits I] 
and III are compressed vertically and laterally constricted at the 
middle. There is nothing in the structure of this foot to warrant 
_ placing it in the genus Morosaurus save its similarity to the foot of the 
American Museum specimen No. 332, which is associated with a 
scapula of the Morosaur type. From foot structure alone it could 
