130 
Coues on the Burrowing Owl. 
Fig. 3. The mandible, from above. 
Fig. 4. The pelvis, from below. 
Fig. 5. The sternum, from below. 
Fig. 6. Tran verse section of thorax, showing a dorsal vertebra, with 
the corresponding pair of ribs, and corresponding section of the sternum. 
Plate III. 
Various bones of the skeleton. 
Fig. 7. Anterior view of skull, the lower mandible having been re- 
moved. 
Fig. 8. H, humerus ; i, ulnar tubercle ; i\ oblique tubercle for radius 
and ulna ; h, radial crest ; S A, S' A', scapular arch; S and S', scapula ; 
C and C', clavicle ; Cr and O', coracoid ; /, perforating foramen. 
Fig. 9. H' , humerus ; Ji", radial crest ; p f, pneumatic foramina ; S A" 
and S A'", scapular arch; S" and S'", scapula; C'' and C'", clavicle; 
Cr" and Cr'", coracoid ; perforating foramen. 
Fig. 10. HA, hyoid arch; a, superior view of atlas; a', the same 
viewed laterally ; b, the axis ; o, its odontoid process. 
Fig. 11. Right carpus of Bubo virginianus, outer aspect, with the 
bones composing it moved partly from their normal positions to show 
articulating surfaces ; rd, radius ; ul, ulna ; s, scaphoid ; c, cuneiform ; 
m, metacarpus ; d, index digit. 
Fig. 12. Right radius and ulna , Speoty to, inner aspect; u, ulna; r, 
radius ; y , articular facet for oblique tubercle of humerus ; y', for ulnar 
tubercle of humerus. 
I-'* Fig. 13. The same bones, inferior surface, when in position and the 
wing closed ; r', radius ; u', ulna. 
Fig. 14. Posterior surface, right metacarpus. The differences in form 
and position of such portion of the articular surface in the metacarpus as 
is shown by z and z in Figs. 11 and 14 between Bubo and Speotyto are 
here seen : flat and rounded below in the first, prominent and pointed in 
the second. 
Fig. 15. Anterior surfaces, right tibia and fibula ; F, fibula ; T, tibia. 
Fig. 16. Posterior surfaces, same bones; F', fibula; T', tibia. 
Fig. 17. Right femur; v, posterior surface ; v' , anterior surface. 
Fig. 18. Anterior surface, right tarso-metatarsus ; m , bony bridge over 
tendons ; j, foramen for anterior tibial artery ; e, facet for outer toe ; l, 
for middle ; t, for inner toe. 
Fig. 19. Posterior surface of same bone ; /, the foramen for the anterior 
tibial artery ; e ", facet for outer toe ; l ", for middle, and t" for inner toe ; 
k, facet for os metatarsale accessorium. 
Fig. 20. A, right os metatarsale accessorium, superior surface ; B, base, 
or inferior surface, of right tarso-metatarsus ; e, facet for outer toe ; i', for 
middle, and i! for inner toe. The section of the shaft shows just above 
the middle facet, on the posterior aspect, ranging near the middle third of 
the bone. 
