1901.] SHUFELDT — OSTEOLOGY OF THE CUCKOOS. 41 



prepared from the alcoholic specimen exhibits some few points of 

 interest. In the skull I find a nasal bone to have the same form as 

 the nasal of an immature Geococcyx, and indeed the entire building 

 up of the skeleton of the head in these two types of Cuckoos seems 

 to be quite similar. With respect to the trachea, my examination 

 of it inclines me to believe that the majority of the rings are entire, 

 especially in the superior half of it. Still more interest attaches to 

 the development of the sternum of this chick of the Yellow-billed 

 Cuckoo, for it, too, ossifies in precisely the same way that that bone 

 does in Geococcyx. Its anterior moiety is already in bone, and in 

 one piece only: the posterior part is in cartilage and distinctly 

 shows the xiphoidal notches, two upon either side of the low semi- 

 developed carina. This is very different from what we find in the 

 GaHincB, a group of birds wherein it was shown that the sternum 

 ossifies from several centres, the pieces not fusing together until the 

 bird is nearly a year old. 



There are eleven vertebrae in the pelvic sacrum of this young 

 Coccyzus, but no special attempt was made to determine how many 

 entered into the formation of the pygostyle. Nor was the micro- 

 scope brought to bear upon its carpus and tarsus with the view of 

 working out the morphology of the embryological elements that 

 enter into the formation of those two interesting joints in this 

 species. 



Synopsis of the Principal Osteological Characters of the 

 Three Subfamilies of the United States Cuculid^e. 



Subfamily Crotophagin^e. 

 Crotophaga ani. 



Crotophaga sulcirostris. 



i. Superior osseous mandible deep in vertical direction, some- 

 what compressed transversely; culmen sharp, decidedly curved, 

 mounded in front of transverse line of cranio-facial hinge. 



2. External narial apertures small, sharply defined and subcircu- 

 lar in outline. 



3. Frontal region broad, convex. 



4. Temporal fossae deeply sculpt \ approach moderately behind. 



5. Postfrontal process short ; squamosal process long. Quadrate 

 large with its processes much compressed. Quadrato-jugal bar 



