VERTEBRAL COLUMN. 399 



shaped articular surfaces are very character- 

 istic of the cervical vertebrae of birds. 



iii. The neural arch is shorter than the centrum, 

 and is deeply notched in the middle line, both 

 in front and behind. .The neural arch is also 

 notched behind, on both sides, for the passage 

 of the spinal nerves. 



iv. The neural spine is rudimentary in the middle 

 cervical vertebrse. 



V. The transverse processes and qervical ribs. At 

 the anterior end of the vertebra an irregular 

 process projects outwards at each side, which 

 is perforated at its base by a large foramen, 

 and is produced at its hinder border into a 

 sharp backwardly directed process. 



This process is really a rib, which, as in 

 the cervical vertebras of the rabbit, is fused 

 with the vertebra ; the foramen at its base 

 transmits the vertebral artery and corresponds 

 to the notch between the capitulum and tuber- 

 culum of the rib. 



vi. The zygapophyses. 



The pre-zygapophyses are borne on the 

 upper surfaces of the transverse processes : 

 their articular surfaces are flat, and face up- 

 wards and inwards. 



The post-zygapophyses project backwards 

 from the posterior border of the neural arch, 



Fio. 71. — Gallus domeBticus. The left half of the skeleton. The skull, 

 vertebral column, and sternum are bisected in the median plane, 

 (o. H. H.) 



A, acetabulum. B, cerebral fossa. OB, cerebellar fossa. CL, clavicle. 



CO, coraooid. CE, cervical rib. C 1, first cervical vertebra. DE, DM, 



DO, preaxial, middle, and postaxial digits of the wing. FE, femur. 



HO, hypocleidium. HTJ, humerus. HY, hyoid. IF, iHo-sciatic foramen. 



IL, ilium. IS, ischium. L, laorymal bone. MCu, metacarpal bone of 



ulnar digit. MW, mandible. MS, metosteon. MT, tarso-metatarsus. 



MT 1, metatarsal bone of first digit. IS, nasal bone. OP, optic foramen. 



Pi premaxilla. PB, pubes. PL, palatine bone. PY, pygostyle. B, radius. 



HO, radial ' carpal bone S, keel of the sternum. SO, scapula. T, tibio- 



tarsuS. TH 4, fourth thoracic vertebra. U, ulna. UC, ulnar carpal bone. 



UP, uncinate process of rib. Z, infra-orbital bar. 



1, 2, 3, 4, 5, the first, second, third, fourth, and fifth digits of the foot. 



