1901.] SHUFELDT — OSTEOLOGY OF THE CUCKOOS. 29 



The fibula has a large head, which is produced backward beyond 

 its shaft. This latter makes a close ligamentous articulation with 

 the fibular ridge of the tibio-tarsus, and at some little distance 

 below it merges into its shaft to become almost indistinguishably 

 fused with it. 



A well-developed subcordate patella, with its apex directed 

 below, is found in the usual tendon in Geococcyx. 



The tarso-metatarsus of the Road Runner is a longer bone than 

 we would be led to expect, had we in our possession but the other 

 long bones of this limb to judge from. 



Its summit presents for examination the two concavities for the 

 condyles of the tibio-tarsus, separated by the mid-tubercle. Behind 

 this we find a short hypotarsus, showing two vertical grooves at its 

 back and two vertical perforations through it. 



The sides and front of this bone are flat, the latter for its proxi- 

 mal half being longitudinally grooved, deepest above, gradually 

 becoming shallower as it descends. Posteriorly it is likewise 

 grooved in a somewhat similar way ; but here the outer wall of the 

 groove is raised as a sharp longitudinal crest, best marked at the 

 middle third of the shaft and gradually subsiding toward the 

 extremities. 



At the distal end we note the three usual trochleas for the basal 

 joints of the toes, as shown in fig. 27 of my former memoir; how- 

 ever, in this zygodactyle bird the outer one of these is extended to 

 the rear in such a manner as to allow the fourth toe to articulate in 

 that direction. 



Of these trochleas the middle one is much the largest and is 

 placed the lowest down ; it is the only one of the three that shows 

 the distinct median groove. The trochlea for the fourth toe is 

 much elevated, while the inner one holds about a mid-position in 

 this respect. 



A well-developed accessory metatarsal, slung by a ligament in the 

 usual way, is found between the shaft and the basal joint of the 

 hallux. The perforating foramen "for the passage of the anterior 

 tibial artery is small and inconspicuous, being at the same time 

 quite low down on the shaft. 



The joints of these podal digits are harmoniously proportioned, 

 both as regards size and comparative length. Beyond being typi- 

 cally zygodactyle, they offer nothing of particular note. 



Before reducing my specimens to skeletons I failed to make any 



