THE I'KLriS. 



13 



indicated by the droop or slope of the croup, whicli is generally greater 

 than that of the Cow. It is more conspicuous in common than in 

 ^vell-bred horses, in which the croup is almost horizontal, and the tail 

 nearly on a level with its highest point. The width of this region also 

 varies not only with the height and volume of tlie animal's l)ody, hut 

 also according to breed— the draught or coarse-bred Horse having a 

 wider croup than the thorough-bred one. This region is constricted 

 from before to beliind, and shows, on the middle line, the spinous pro- 

 cesses of the sacrum and the first coccygeal vertebrte ; and on each 

 side the channels into which open the four sacral foramina. 



The inferior region is nearly horizontal, and is slightly convex. 

 Formed by the pubic and ischial bones, it offers in the middle the 

 symphysis pubis, on each side the subpubic channels and the obturator 

 foramen, and outwardly the cotyloid cavities tlirough which the pelvis 

 rests on the posterior limbs. 



Fig. 6. 



LONCITl'DINAL SECTION OK A MaKK's PeLVIS 



The lateral regions are more extensive than the others ; they are in- 

 clined downwards and inwards, and are wider before than behind. 

 On each are observed the crest of the ilium and tlie two anterior iliac 

 spines, the external iliac fossa, the great sciatic notch, the spine of 

 the ischium, the small sciatic notcli, and the tuberosity of the ischium. 



The internal surface (Fig. 6), as has been already mentioned, is 

 formed partly of bony and partly of ligamentous walls, and circum- 

 scribes the pelvic cavity, which is a continuation of that of the abdomen, 

 and with which it communicates by a wide osseous circle — the anterior 

 opening or inlet of the pelvis. A transverse section of this canal shows 

 that it is oval-shaped, the largest portion being towards the pubis, and 

 the narrowest towards the sacrum. 



The internal surface is more regular than the external, but it cannot 

 be divided into two portions like the liuman pelvis, the inner aspect 

 of the ilia not being excavated to form an anterior cavity. It may, 

 however, be considered as having /owr concave i)lanes, an anterior opening 

 or inlet, and a jwsterior opening or outlet. 



The superior, sacral, or rectal plane, or roof of tlie p)clvis is formed 

 by the lower face of the sacrum, and is in contact ■with the rectum, 



