24 
UPPEK MAMMAL GALLERY. 
and assists in locomotion during the awkward attempts o£ most 
Bats to walk on all-fours. The hind-limbs, which in ordinary 
Mammals propel the body forwards, are almost entirely relieved 
of that office, being singularly weak and feeble, and of little use 
except while the animal is flying, asleep, or resting. In repose 
Bats hook the sharp claws, with which the hind toes are 
furnished, on to some support, and remain suspended with the 
head downwards until again ready to fly. 
cl, clavicle ; cv, cervical vertebrae : d, dorsal vertebrae ; fh, fibula ; fm, femur ; 
h, humerus; hx, great toe, or hallux ; /, lumbar vertebrae; wc, meta- 
carpals; mt, metatarsals; pA, phalanges; pelvis; px, thumb, or 
pollex ; ?•, radius ; s, sacral vertebrae ; sc, scapula ; skull ; tb, tibia ; 
ts, tarsus ; w, ulna. 
In the skeleton (fig. 13) the fore-arm is formed almost entirely 
by the radius (r), the %dna (ii) being rudimentary. The thumb 
{fx) is short, free from the flying-membrane, and provided with 
a claw {p]}) ; while the other fingers are long, slender, and 
clawless, with the exception of the index, corresponding to our 
