20 
CENTRAL HALL. 
that of supporting the body on the ground. It stands on the 
tips of the toes of its elongated slender feet. 
6. A Porpoise, adapted solely for swimming in the water. 
The fore-limbs are converted into flattened paddles, and the 
hind-limbs entirely absent, their function being performed 
by the tail. The rudimentary pelvic bones are preserved. 
The rest of the case is occupied by details of the skull in 
some of its principal modifications. At the top are diagrams 
of the structure of bone and cartilage as shown by the micro- 
scope. 
Fig. 7. — Skeleton of a Fox-Bat {Fteroims medium). 
cZ, clavicle ; ci?, cervical vertebrae ; d, dorsal vertebrsp ; fh, fibula; /m, femur; 
7i, humerus; hx, great toe, or hallux ; I, lumbar veitebrse ; wc, metacarpals ; , 
mf, metatarsals ; p/t, phalanges; jov, pelvis; jjx, thumb, or pollex : r, radius; j 
.s, sacral vertebrae ; sc, scapula ; sh, skull ; fb, tibia ; ts, tarsus ; u, ulna. j 
In the wall-case on the opposite (north) side of the bay the I 
outline of the osteology of mammals is continued by illustrations j 
of the structure of the limbs. At the top of the case is a 
diagram showing the correspondence of the hand and the foot 
in their complete typical form, with the names applied by 
anatomists to the different bones. The series of specimens 
l)elow show the principal deviations which actually occur from 
