Fig. 55. Gallus bankiva var. domesticus. The left half of the Skeleton. The skull, vertebral column, and sternum are bisected in the median plane. (After Marshall and Hurst.)
A, acetabulum. B, cerebral fossa. CB, cerebellar fossa. CL, clavicle. CO, coracoid. CR, cervical rib. C 1 = one, first cervical vertebra. FE, femur. HC, ventral end of clavicle. HU, humerus. HY, hyoid. IF, ilio-sciatic foramen. IL, ilium. IS, ischium. L, lachrymal. MC 3, postaxial metacarpal. MN, mandible. MS, xiphoid processes. MT, tarso-metatarsus. MT 1, first metatarsal. N, nasal. OP, optic foramen. P, premaxillae. PB, pubis. PL, palatine. PY, pygostyle. R, radius. RC, radial carpal. S, keel of sternum. SC, scapula. T, tibio-tarsus. TH 4, fourth thoracic vertebra. U, ulna. UC, ulnar carpal. UP, uncinate process. Z, infra-orbital bar. 1, 2, 3, 4, first, second, third and fourth digits of pes. 3, pre-axial, 4, middle, and 5, postaxial digit of manus.
Fig. 55.
CHAPTER XVIII.
THE SKELETON OF THE WILD DUCK (Anas boschas).
I. EXOSKELETON.
The exoskeleton of the Duck and indeed of all birds is entirely epidermal in origin. Its most important part consists of feathers, but it includes also the following horny structures:—