352 NEW YORK STATE MUSEUM 



Upon comparing the pelvis of this cuckoo with the correspond- 

 ing bone in Cuculus, a number of very marked differences are to be 

 observed, it being much less typically cuculine in the latter than it 

 is in the former species. In Coccystes the pelvis is comparatively 

 narrow as compared with its length, and deep from above, down- 

 ward, whereas in the common cuckoo it is considerably compressed 

 in this direction, rendering the pelvic basin more shallow, while, 

 as a whole, the bone is short and wide. Both have open " ilioneural 

 canals," with a pronounced " sacral crista " standing between them, 

 better marked in Coccystes, where, too, the anterior moieties of the 

 ilia closely resemble those parts in Geococcyx. Posteriorly, on the 

 dorsum, we meet with a few scattered, intervertebral foramina. 

 Viewed laterally, it is to be noted that the outstanding of the ilium 

 over the ilioischiac foramen is fairly well marked in Coccystes, being 

 much less so in Cuculus canorus, in which species, too, 

 the prepubic spine is so much aborted as to hardly attract attention, 

 and this well known cuculine character is only slightly more con- 

 spicuous in the former bird. On the posterior pelvic margin there 

 is a shallow ilioischiac notch in Cuculus which is absent in Coc- 

 cystes, while the latter has the ilium, on either side, produced 

 close to the first caudal vertebra, as a distinct apophysis, a character 

 not present in the common cuckoo. Both have the posterior pubic 

 styles extended far backward as slender curved rods, very different 

 from anything we meet with in such a species as Geococcyx. 



Indeed, were I handed a specimen of the pelvis of an adult 

 Coccystes glandarius, not having been informed as to 

 what species of bird it belonged, I would, without hesitation, pro- 

 nounce it to be from some representative of the north temperate 

 tree cuckoos ; but, were the same test made with a pelvis of 

 Cuculus canorus, no other pelves being at hand, in either 

 case, for comparison, it would not be an altogether unpardonable 

 mistake were I to decide, offhand, that it was a pelvis from some 

 caprimulgine form, somewhere between a Chordeiles and an An- 

 trostomus, with more or less cuckoo in it. 



Appendicular skeleton. Pectoral limb. Whatever else may be 

 said about the skeleton of Coccystes, the bones of its wing are those 

 of a true representative of the Coccyges, that is, of the arboreal 

 type. Proportionately, their shafts are much less curved than we 

 find them in Geococcyx, and in agreement with that genus the 

 humerus alone is endowed with pneumaticity, the pneumatic 

 foramen, however, at its usual site, being very small, which is 



