AaS Lucas Ofi the Affinities of Cha:iura. [October 



Trogojt resemble each other closely and are intei-mediate in form 

 between those just described. In these birds the manubrium is 

 absent, the costal processes large, and the xiphoid border marked 

 with two rounded excavations. 



The coracoids of both Chc€t7i7-a and Trochihis are short and 

 stout, and in both birds these bones, instead of resting in the 

 usual coracoid groove, articulate with a raised oval facet, forming 

 a shallow ball and socket joint. Wiiile there is as wide a difference 

 between the coracoids of CJicctttra and TrocJiihis ■.\'&\ix. Slnifeldt 

 points out between Trochihis and Panyptlla, this discrepancy is 

 almost entirely due to the unusual development of the inner 

 edge of the bone in TrocJiihis. This is so great as to make the 

 distal end of the coracoid as wide as the proximal, while the 

 prolongation of the clavicular process and its fusion with the 

 scapular process forms a tendinal foratnc//. There is nothing of 

 this in CJuvUira^ but there is a good sized foramen correspond- 

 ing to the lower foramen of Troc//il?is. and the coracoid as a 

 whole is entirely difierent from the long, slender, imperforate bone 

 we find in Chclidon and other typical Passeres. Here, again, 

 Chordeiles stands intermediate between CJuvtura and Chelidon^ 

 the coracoid being moderately stout, but long and imperforate. 

 The furculum of Trochilns is widely U-shaped, has an almost 

 rudimentary hypocleidium, is devoid of an anterior process at its 

 articulation with tlie coracoid, and is so short as to reach but half 

 way to the anterior angle of the sternal keel.* 



The furcidum of CJuvtura agrees with that of TrocJiihis in all 

 respects save width, and even here it greatly exceeds the corres- 

 •ponding bone of CJich'do7i. The furculum of CJicJidoii^ more- 

 over, reaches from coracoid to angle of sternum, has clavicular 

 ends anteriorly expanded, and a large backwardly directed hypo- 

 cleidium. 



The point of the scapula has a downward droop in TrocJiiliis 

 that is wanting in that of CJicctiira., but in the nestling of this 

 latter bird the cartilaginous supra-scapula is bent downward at 

 an angle even greater tlian in TrocJiihis. The curious shape of 

 the humerus in TrocJiihis and CJicctura is due to the total sup- 



* This shortness is not only apparent bnt real, and is not due to the depth of keel. 

 Owing to the shortness of the coracoids the furculum of Chclidon will reach from 

 scapula to angle of keel in Chcefura, and that of Vireo will do the same for Campylop- 

 terus. 



