500 SHUFELDT. [Vol. XVII. 



Passing now to the shoulder-girdle we find all of its parts 

 very well developed. 



A coracoid has a length of shaft above the average ; and it 

 is straight and subcylindrical in form. As usual its sternal 

 extremity is dilated, especially to its outer side, while on the 

 other hand the " coracoidal head" is not much enlarged in this 

 pigeon. The scapular process is conspicuous, and in addition 

 to giving room for the articulation of the scapula, it curves, as 

 a flattened lamina of bone, inwards and then forwards to come 

 near in contact with the os furcula. This latter element of 

 the girdle is very slenderly constructed ; it being of the typical 

 U-shaped pattern, with the limbs of nearly uniform caliber. 

 Its free ends above are but very moderately enlarged, and the 

 hypocleidium may be said to be entirely absent. Either head, 

 upon its outer aspect, develops a feeble shoulder to rest in 

 articulation against the head of a coracoid. Below, the os 

 furcula is connected with the keel of the sternum by ligament, 

 a mesial band passing between two bones. 



The glenoid cavity, as usual, is formed by the coracoid and 

 scapula, in the proportion of two-thirds contributed by the 

 former, to the remaining one-third of the latter. A scapula is 

 of the usual cimeter-form pattern, — the straight variety ; 

 its anterior moiety is thickish and narrow, being expanded and 

 flattened posteriorly, where it is obliquely truncated from 

 within backwards and outwards to a point. In the natural 

 skeleton this apex about reaches to the front border of the 

 last dorsal rib. 



With regard to the remainder of the trunk skeleton in 

 Zenaidnra viacroiira, as compared with what has just been 

 described for Ectopistes, we find but few and comparatively 

 unimportant differences. Among the most evident of these 

 are those seen in the sternum, where the external-xiphoidal 

 processes are more slender and curved, and do not present the 

 distal truncation seen in the Passenger pigeon. The internal- 

 xiphoidal processes in Zenaidnra unite by their postero-internal 



intern al-xiphoidal fenestras and external-xiphoidal processes. Leucosarcia picata 

 appears to have the pattern of the bone much as we find it in Starnanas. Goura 

 has quite a unique sternum for a pigeon, so far as I am at present aware. 



