VERTEBEAL COLUMN 357 



the vertebral column with which the pelvis is connected; 

 (4) the small number of the caudal vertebrEe, and the fusion 

 of the posterior ones to form the pygostyle ; (5) the absence 

 of epiphyses. 



The column may be divided into cervical, thoracic, sacral, 

 and caudal regions; the boundaries between these being 

 ill-defined, and the sacral portion being further divisible into 

 three sub-sections. 



1. The cervical vertebrae. The distinction between cervical 

 and thoracic vertebra is an arbitrary one, of no mor- 

 phological value, and is not easy to determine in the 

 fowl. It is usual to count as the first thoracic 

 vertebra, the most anterior one which bears a rib 

 articulating with. the sternum, and to name all the 

 vertebra in front of this one cervical. Beckoned in 

 this way there are sixteen cervical vertebrae, the two 

 hindmost of which bear well-developed and movably 

 articulated ribs, which, however, do not reach the 

 sternum. 



In the following description the vertebral column 

 is supposed to be placed horizontally. 



a. A typical cervical vertebra : — any one from the sixth 

 to the tenth. 



The parts of the vertebra are the same as in the 

 rabbit, except that there are no terminal epiphyses : 

 the chief pecuharities are the foUowiag. 



i. The vertebra is very long and light, as compared 

 with the cervical vertebra of a rabbit. 



Fig. 46. — Gallus bankiva, var. domesticns. The left half of the skeleton. 

 The skull, vertebral column, and sternum are bisected in the median 

 plane, (c. h. h.) 



A, aoetabnlmn. B, cerebral fossa. CB, cerebellar fossa. 

 CL, clavicle. CO, coracoid. CRj cervical rib. C 1. first cervical vertebra. 

 PB, femur. HO, hypocleidiam. HTT, humerus. HT, byoid. IP, ilio- 

 sciatic foramen. Hi, ilium. IS, ischium. L, lacrymal bone. MC 3, meta- 

 carpal bone of third digit. MM", mandible. MS, metosteon. MT, tarso- 

 metatarsus. MT 1, metatarsal bone of first digit. M", nasal bone. OP, optic 

 foramen. P, premaxilla. PB, pubes. PL, palatine bone. PT, pygostyle. 

 R, radius. KG, radial carpal bone. S, keel of sternum. SO, scapula. 

 T, tibio-tarsus. TH 4, fourth thoracic vertebra. U, ulna. UC, ulnar carpal 

 bone. TTP, uncinate process of rib. Z, infra-orbital bar. 



1, 2, 3, 4, the first, second, third, and fourth digits. 



