_a_, Wing, _b_, shaft, _c_, external angle, _d_, anterior border, _e_, internal angle, _f_, gluteal line of ilium; _g_, great sciatic notch; _h_, smooth, _i_, rough part of ventral surface of ilium; _k_, psoas tubercle; _l_, ilio-pectineal eminence; _m_, acetabular branch, _n_, symphyseal branch of pubis; _o_, obturator foramen; _p_, _p′_, ischium; _q_, _q′_, tuber ischii; _r_, symphysis; _s_, ischial arch; _t_, _t′_, superior ischiatic spine; _u_, acetabulum; _v_, epiphyseal line. (Ellenberger-Baum, Anat. d. Haustiere.) ] The =tarsus= comprises seven bones. The tibial and the fibular tarsal resemble in general those of the ox. The axis of the tibial is, however, slightly oblique downward and inward, and its distal end bears a double trochlea for articulation with the central and fourth tarsals. The tuber calcis is deeply grooved posteriorly. The central tarsal is narrow transversely and thick. Its proximal surface is deeply concave, and the posterior bears a large tubercle. The first tarsal is high and narrow; it articulates with the central and second tarsals and the second metatarsal bone. The second tarsal is small and somewhat prismatic; it articulates with the central above, the third in front, the first behind, and the second and third metatarsals below. The third tarsal is much larger, and is compressed from above downward, wide in front, narrow behind. It articulates with the central tarsal above, the third metatarsal below, the second tarsal internally, and the fourth tarsal externally. The fourth tarsal is large. Its external face is crossed by an oblique groove for the tendon of the peroneus longus. The internal surface articulates with the central and third tarsals. The proximal surface supports the tibial and fibular tarsal bones, and the distal surface rests on the fourth and fifth metatarsals. It ossifies from two centers. The four =metatarsal bones= resemble the corresponding bones of the fore limb, but are somewhat longer. The proximal ends of the third and fourth each have a considerable projection behind; the process on the third has a facet for articulation with a discoid sesamoid bone. The second and fifth are placed more on the posterior aspect of the large bones than is the case in the fore limb. The first and second =phalanges= are a little longer and narrower than those of the fore limb. SKELETON OF THE DOG VERTEBRAL COLUMN The vertebral formula is C_{7}T_{13}L_{7(6)}S_{3}Cy_{20–23}.