1 1 1.1 GENERAL CHARACTERS. 



15 



the last named animal and the caudal vertebrae of many- 

 others. This is termed a hypapophysis. Most commonly 

 there is not even a trace of any such process. 



3. From the sides of the lov/er part of the arch, or from 

 the body, lateral processes project more or less directly out- 

 wards. These are called transverse processes. There may be 

 but one, or there may be two, superior and inferior, on each 

 side of a vertebra. In the latter case the superior is some- 

 times called a diapop/iysis, and the inferior a parapopJiysis ; 

 though it is questionable whether the processes to which 

 these terms have been applied can always be regarded as 

 stricdy homologous. 



4. Besides these principal laterally projecting processes, 

 there are often others arising from the side of the arch, more 



JJZ 



Fig. 4. — Side view of first lumbar vertebra of Dog {Ca7iis familiaris), f. s spinous 

 process ; az anterior zygapophysis ; pz posterior zygapophysis ; m metapophysis ; 

 a anapophysis ; t transverse process. 



especially developed in the lumbar region, though by no 

 means constant even there. Of these there may be one or 

 two on each side. They have often been called accessory 

 pi'ocesses ; but in the more precise system of nomenclature 

 introduced by Professor Owen, the one which is situated 

 highest on the arch (see Fig. 4, w), projects more or less 



