64 ODOXTORXITHES. 



The head and tubercle are very similar to those in the preceding rib, but 

 the tubercular process is shorter and stouter, and more inclined toward the 

 body of the vertebra. The shaft is slender, and tapers gradually below to 

 the extremity, which is obtuse, and somewhat incurved. This rib had a 

 small uncinate process (Plate IX, figure 10), articulated to the posterior 

 margin of its lower third. This process was placed nearly at right angles 

 to the rib, and overlapped the outer surface of the rib which followed. 



The Fourth Rib (Plate IX, figure 4), which was attached to the 

 eighteenth, or first dorsal, vertebra, is much larger than the preceding, 

 although its upper portion is very similar. The tubercular facet is less 

 convex, and its supporting process- shorter than in the rib last described. 

 The shaft of this rib is more twisted, and flattened. The distal extremity 

 is expanded, and terminates with an articular facet for union with the first 

 sternal rib. The uncinate process (Plate IX, figure 11) is larger and 

 longer than the preceding one. It was directed upward, and backward, 

 and joined the rib from above at an acute angle. 



The Fifth Rib (Plate IX, figure 5) is slightly longer than the fourth, 

 and very similar to it. Unfortunately, the articular parts of the upper end 

 of this rib are wanting in the most complete series (number 1206), but its 

 general character is made evident from its position, and connection. The 

 tubercle had a similar position to that of the preceding one, but was 

 shorter, and nearly sessile. The uncinate process on this rib was large 

 (Plate IX, figure 12), and, in position, extended upward and backward 

 over the two following ribs. The distal extremity of this rib is very 

 similar to that of the preceding one. 



The Sixth Rib (Plate IX, figure 6) is considerably larger than the 

 fifth, and its shaft is flatter, more twisted, and considerably more curved. 

 The tubercular facet is sessile, and raised but very little above the neck. 

 The uncinate process is large, and spatulate (Plate IX, figure 13), and was 

 directed upward and backward. It is somewhat constricted a short distance 

 above its articular face. The distal end of this rib is expanded, and widest 

 at the extremity, which is abruptly truncated. 



