THE OSTEOLOGY OF VULVES MACROTIS. 405 



The atlas is the broadest bone of the entire column, though the spreading 

 transverse processes of the last lumbar gives it nearly an equal breadth. No 

 vertebra in the entire chain at all resembles the atlas in form. It is about twice 

 as wide as it is long, and its big neural canal is bounded on either side by the 

 narrow cap-like articulations for the condyles of the occiput. Either quadrate, 

 horizontal transverse process is pierced, near its middle, by the vertebrarterial canal, 

 the foramen for the first spinal nerve being anterior to this just within the supero- 

 anterior border close to the condyloid cup. A rudimentary hypapophysis exists, 

 but the neural spine is entirely absent. There is a smooth articular facet present 

 for the articulation of the long, peg-like odontoidal apophysis of the axis. It is 

 situated in the middle line interiorly within the neural canal. The thin, sharp, 

 lofty neural spine of the axis extends the entire length of that bone, and projects 

 conspicuously beyond the centrum in front. The haemal spine is likewise laterally 

 compressed, but it is feebly developed and principally confined to the hinder part 

 of the centrum' of the vertebra. This is likewise the case with the third, fourth 

 and fifth cervicals, this inferior spine being absent upon the sixth and seventh 

 cervicals, as it is completely so from the balance of the vertebral column. Neural 

 spines, however, are found upon the last five cervicals, where they increase in 

 height and sharpness as we pass backward in the direction of the thorax. Large, 

 strong zygapophyses characterize the cervicals, and the transverse processes are 

 thin, sharp and conspicuous. In the second to the sixth inclusive they are bent 

 downward and project beyond the centra both in front and behind. These processes 

 become suddenly contracted in the seventh cervical, where they more closely 

 resemble those in the pre-dorsal series. Upon either side the vertebrarterial canal 

 passes through all of the cervicals, save the seventh or last one. 



Metapophysial processes are first seen feebly pronounced on the third cervical, 

 they grow stronger and stronger from before backward to include the sixth. On 

 the seventh they are more or less aborted, as they are upon the first five dorsals, 

 when they again make their appearance upon the sixth dorsal, as a feeble pair of 

 minute spines pointing backward. After this they gradually increase in size to 

 diminish again on the fourth lumbar, being entirely absent in the fifth, sixth and 

 seventh lumbar, and the remaining part of the column. 



The ten first dorsal vertebras are more or less like each other, while the last 

 three dorsals, although they support true ribs, resemble the first lumbar. In the 

 ten first dorsals the neural spines are very prominent, being well separated from 

 each other in the articulated skeleton, lofty, laterally compressed, narrow, with 

 nearly parallel anterior and posterior borders. This spine in the leading dorsal or 

 thoracic vertebra has a height of two centimeters, and it is nearly perpendicular to 

 the longitudinal axis of the centrum. In the tenth dorsal the neural spine is but 

 one centimeter high, and the process leans backward. Between these two extremes 

 a gradual change in form and height takes place from the first to the tenth inclu- 

 sive. Thoracic vertebrae have their zygapophyses much reduced, but the inter- 

 locking among them is very firm. Transverse apophyses are also inconspicuous in 



