38 SHUFELDT — OSTEOLOGY OF THE CUCKOOS. [Jan.4 r 



ened and strengthened to act as tie-beams to brace the line of 

 pressure between the femora. 



In Ceniropus superciliosus the prepubic spines of the pelvis are 

 conspicuously produced, while the postpubic element upon either 

 side extends but very little beyond the bone above it posteriorly. 

 Then in the curious pelvis of this Cuckoo the ilio-neural grooves 

 are very short and are arched over simply by the much antero-pos- 

 teriorly compressed arches of one of the included vertebrae (PI. II, 

 Fig. 13). In Diplopterus ncevius these grooves are open and 

 shallow, while the slender postpubic elements sweep far out behind, 

 and the prepubic spine is barely noticeable. In other words the 

 pelves of these two Cuckoos are essentially very different. Centro- 

 pus has all the main cuculine characters well pronounced, while the 

 pelvis in Diplopterus closely resembles that part of the skeleton in 

 some of the passerine birds. 



Several interesting points are presented on the part of the bones 

 composing the shoulder-girdle in Coccyzus. A scapula is compara- 

 tively not quite as long nor as narrow as we find it in Crotophaga, 

 and its posterior fourth, in some specimens, is inclined to be broad- 

 ened, and bent slightly outward. At the sternal end of a coracoid, 

 at its outer side, we meet with a conspicuous, upturned and sharpened 

 process. The hypocleidium of the os furcula of some specimens of 

 Coccyzus americanus is of a peculiar form, having a crescentic shape 

 with the concave aspect of the line looking toward the manubrium 

 of the sternum. 



Comparatively shorter and broader than we find it in Geococcyx, 

 this latter bone nevertheless practically agrees with the sternum of 

 the Ground Cuckoo and with Diplopterus. 



Its deeper keel has still the true cuculine pattern, and there are 

 two notches upon either side of it, behind, and these are deep in the 

 last named genus. Of the xiphoidal processes thus formed the 

 strong outer pair possess dilated hinder ends, while the weaker 

 inner pair are, upon either side, inclined by their posterior tips 

 toward the postero-external angles of the mid-portion of the 

 xiphoidal prolongation. In some of the Bornean Meropidce these 

 tips fuse at the angular points just mentioned. As in all N. Ameri- 

 can Cuculidce, the sternum is a very thoroughly pneumatic bone. 1 



1 A number of the skeletal characters in the case of Coccyzus are liable to 

 vary and depart to some extent from the descriptions I am here giving ; among 

 which are the depth of the xiphoidal no'ches ; the form of the hypocleidium of 



