1881. ] on the Feet of Mammata. 543 
III. The trochlear ridges and keels at the various movable 
articulations of the limbs. These are as follows: 
fi peti downward 
. Intertrochlear crests of the humerus. 
z. On the carpal end of the radius. 
Yt: Netacrpl distal ends, 
6, Tibia dis 
é. SNancadials 7 
2. Looking ‘apy 
B. Astragalus, edge 
y: Astragalus distally boars ster 
6, Phalanges (very weak). 
The following sleet may be made respecting the struc- 
tures included under division III: The trochlear keels which 
look downwards are much the most prominent and important. 
Those enumerated as looking upwards are weak and insignificant, 
or of a different character from the down-looking ones. The 
latter are all projections from the middles of the ends of the 
respective elements. The up-looking are generally projections of 
the edges of =. Such are the lateral crests of the astragalus, 
s 
bees 
Fig. 1, Fic. 2. 
Fic, 1.—Right osterior foot of f Corvphodon from New Mexico, one- 
ze-t nat size Frc Report 1 Ex pl. W. of a pes i Mer G .M. Weer Pl, ux. 
—Right st foot of Aphel lodus Cope, from Colorado, one- 
halt'n natural si in se rom Repor rt U.S. é pleles mess Tennis FE. v. Hayden, IV, Pl. XxX. 
and the adjacent edges of the cuboid and navicular bones which 
