THE LIMBS AND GIRDLES. 587 



expanded transverse processes of the ninth or sacral 

 vertebra. Each limb of the V is an ilium ; the united 

 posterior part consists of a fused pair of ischia, and a ventral 

 cartilaginous pubic portion. Ilium, ischium, and pubis unite 

 in bounding the deep socket or acetabulum with which the 

 femur articulates. 



The skeleton of the hind-limb consists of a thigh bone or 

 femur, a lower leg formed from the united tibia and fibula, 

 an ankle region or tarsus including two long proximal 

 elements the astragalus or tibiale and the calcaneum or 



op.l-J 

 cb 



I n in 



FIG. 318. Brain of frog. After Wiedersheim. 



I. DORSAL ASPECT. 0./., Olfactory lobes; c.k., cerebral hemi- 

 spheres ; P., pineal body, rising from region of optic thalami ; 

 op. 1., optic lobes; cb., rudimentary cerebellum ; M.O. y medulla 

 oblongata. 



II. VENTRAL ASPECT. The numbers indicate the origins of the 

 nerves, ck., Optic chiasma; T.C., tuber cinereum (infundib- 

 ulum); H., hypophysis. 



III. HORIZONTAL SECTION. /.., i and 2, lateral ventricles of 

 cerebrum ; P.m., foramen of Monro; F., 3 and 4, third and 

 fourth ventricles ; Ag., cavities of optic lobes and aqueduct of 

 Sylvius from third to fourth ventricle. 



fibulare and three imperfectly ossified distal elements, five 

 metatarsal bones, and five toes. The first toe or hallux 

 has two phalanges, the second also two, the third three, the 

 fourth four, the fifth three, and, finally, 'outside the hallux 

 there is a " calcar," which looks like an extra toe, and con- 

 sists of three pieces. The astragalus is in line with the first 

 toe. The long bones of the skeleton show readily separable 

 calcified terminal caps. 



