1901.] SHUFELDT — OSTEOLOGY OF THE CUCKOOS. 37 



are, comparatively speaking, large and conspicuous, especially in 

 the last-named species (see PI. II, Fig. 15). 



Posteriorly, the crotophyte fossae of Coccyzus more nearly ap- 

 proach each other than they do in Geococcyx, and a pterygoid in the 

 former species develops a raised, thin crest on the superior aspect 

 of its anterior moiety, a character I do not find at all in the Road 

 Runner. These fossae are very deep in Centropus superciliosus and 

 nearly meet behind, while in Diplopterus ncevius they are shallow 

 and widely separated posteriorly. 



Coccyzus may or may not possess a minute spiculiform vomer. I 

 have examined adult fresh specimens to decide this very point, and 

 have found old individuals where this element was undoubtedly 

 missing, while I have found it very feebly developed in others. 1 



Turning next to the remainder of the skeleton we find eighteen 

 free vertebrae between skull and pelvis in the spinal column, as in 

 Ce?itropus and Diplopterus ncevius, and their characters are essen- 

 tially the same as I have described them for Geococcyx. This state- 

 ment also applies to the caudal vertebrae, but the number and 

 arrangement of the ribs do not either agree with the Ground 

 Cuckoo nor with the Ani. 



There are three pairs of free cervical ribs ; four pairs of dorsal 

 ribs that connect with the sternum by haemapophyses ; and finally, 

 a pair of pelvic ribs that lack epipleural appendages and whose 

 costal ribs do not quite succeed in reaching the costal border of the 

 sternum. This last pair appear to be absent in Diplopterus ncevius 

 (PL II, Fig. 14). 



The pelvis is cuculine in its general character, but differs consid- 

 erably from the pelvis of Geococcyx. Its ilia curl but little over the 

 ilio-ischiac foramen upon either side, and the coalescence between 

 the internal margins of the ilia and the sacral crista is more 

 thorough. The prepubis is very small. In none of the N. American 

 Cuckoos are the parapophyses of the sacral vertebrae opposite the 

 acetabulae upon the ventral aspects of the pelvis, especially length- 



1 Especial attention is invited to the morphology of the external narial aper- 

 tures of the superior osseous mandible of Geococcyx, Coccygus, and Crotophaga. 

 In the latter they are clean cut, subcircular, and comparatively small : while in 

 Geococcyx and Coccygus they are large and subelliptical, but more or less masked 

 by the bony lamina that extends over them, leaving in the case of the first-men- 

 tioned species a rather small anterior narial aperture, with usually two apertures 

 in Coccyzus, an anterior and a posterior one. They are small and fairly clean cut 

 in Diplopterus ncevius, but large and triangular in Centropus. 



