36 SHUFELDT — OSTEOLOGY OF THE CUCKOOS. [Jan. 4, 



is carried to its mininum, and almost entirely disappears, the border 

 of the bone in question well-nigh becoming entire. 



Being constructed upon exactly the same principle, I find noth- 

 ing especial requiring description in the pectoral limb of Crotophaga, 

 further than what has already been given above for Geococcyx. 

 (See PI. II, Fig. 9.) Practically the characters are the same in all 

 the bones composing the skeleton of this extremity in these two 

 Cuckoos, and I also find that a small os humero-scapulare is present 

 in the Anis. 



With respect to the pelvic limb, this statement applies with almost 

 equal truth, though in Crotophaga the procnemial process of the 

 tibio-tarsus is not as well developed ; it has but a single tendinal 

 perforation through the hypotarsus of the tarso-metatarsus, and that 

 process is peculiarly capped off by a plate of bone ; and, finally, 

 in Crotophaga the longitudinal excavation adown the anterior 

 aspect of the tarso-metatarsus is, comparatively speaking, much 

 deeper than it is in Geococcyx. Aside from these apparently minor 

 difference's the skeletons of the pelvic limbs of these two cuculine 

 types are fundamentally the same. 



The Genus Coccyzus Osteologically Considered. 



Forms of this group, as C. americanus, have a skull, with its asso- 

 ciated skeletal parts, very much like Geococcyx, and quite different 

 from what we have just described above for Crotophaga. (See PL 

 II, Fig, 7.) So much is this the case that I will not enter upon a 

 detailed description of the skull of Coccyzus but rather give some 

 of the chief departures it makes from the corresponding characters 

 as they occur in that part of the skeleton of the Ground Cuckoo. 



In Coccyzus, and essentially too in Ce?itropus and Diplopterus, the 

 structure of all the osseus parts of the superior mandible practically 

 agree, both in form and relations, with what we find in Geococcyx. 

 The former species, however, has a relatively shorter and broader 

 bill, but its maxillary processes, at the same time, are not only rela- 

 tively, but (usually) actually longer than they are in Geococcyx. 



A lacrymal bone in Coccyzus has its descending portion only 

 represented by an outwardly-curved, delicate spicula of bone ; the 

 structure as a whole reminding us very much of the lacrymal as we 

 find it in many of our Tetraonidce. 



This is by no means the case, however, in Centropus and in 

 Diplopterus nozvius, where in both these genera the lacrymal bones 



