FREE APPENDAGES MAMMALS 295 



Chiroptera. — The humerus, which lacks the ulnar foramen, has strong 

 tuberosities in most genera. The radius is longer than the humerus, sometimes 

 as long as the body. Only the distal part of the ulna, which fuses with the radius, 

 and the olecranon persist. The wrist (fig. 318) has two well-marked joints, one 

 between radius and carpus, the other between carpus and metacarpus. The 

 centrale and the three proximal carpal bones are usually fused. Carpale i 

 supports the pollex, the only normal digit, the others being very long to support 

 the wing. The pisiforme is in the middle of the carpus. The femur has no 

 third trochanter, the fibula is degenerate, only its distal end, fused with the tibia, 

 remaining. Talus and calcaneus are long, the latter with 

 an osseous spur. The five toes are clawed. 



Dermoptera, represented only by Galeopithicus, has 

 a scapho-lunatum and no free centrale. Digit 5 of the 

 manus is longest, followed by 4; i is much shorter than the 

 others. The small fibula is complete, but does not reach 

 the calcaneus. The five clawed toes are nearly equal. 



Edentata have the humerus long and slender in 

 sloths, in other genera (figs. 272,316) it has strong tuber- fi^. 318. — Carpus 

 osities and an entepicondylar foramen. Radius and ulna of fetal Rhinolophus 

 are separate and in Xenarthra have slight rotational cenu-aleT^i,' interme- 

 powers. Radiale and interemdium are separate in Xenar- dium; u, ulnare; 1-5, 

 thra and Tubulidentata, fused in pangolins. The other carpaha; I-V, meta- 

 carpal bones are usually distinct, except that a centrale only 



occurs in Tamandua, while the distal carpals may be united, and in sloths, fused 

 with the partly united metacarpals. The carpal bones may be increased by 

 sesamoids. The number of digits in the manus ranges from five in Pholidota 

 and some Xenarthra, to four in other Xenarthra and the aard vark, digits 3 and 2 

 usually the larger. The femur, short in sloths where it lacks strong trochanters, 

 has a third in Tubulidentata and most Xenarthra. The crural bones are 

 separate in sloths and anteaters; elsewhere tibia and fibula fuse, proximally or 

 distally, or {Dasypus) at both ends. Fusion of the tarsal bones is common, and 

 in sloths the tarsalia may unite with the metatarsals. Usually the foot is 

 pentadactyle, digit i being absent occasionally and 5 in a few. The distal 

 phalanges of all may be grooved or cleft for the claws. 



RoDENTiA commonly have an entepicondylar foramen in the humerus. 

 Radius and ulna are always separate, but radiale and intermedium are united 

 and there is a radial sesamoid, even when the pollex is reduced. Prepollex and 

 postminimus are common, the former sometimes with a claw, the latter may have 

 two phalanges. There may be a third trochanter on the femur; tibia and fibula 

 are separate or fused distally, the fibula rarely articulating with the calcaneus. 

 A prehallux is common, and both fore and hind feet almost always have five digits. 



Carntvora have the limbs very different in the two suborders. In the 

 Fissipedia they are adapted to terrestrial locomotion; in the Pinnipedia (seals, 

 etc.) for aquatic life. The long humerus of the Fissipedia has an ulnar foramen 

 in recent cats and some Mustelids; its tuberosities are large and there is a large 

 deltoid process and a deep fossa for the olecranon. Ulna and radius are separate 



