272 THE MUSCLES. 



flexor ia covered by the perforatua, and its oleeranian portion, thicker than in the other 

 animals, is only united to the principal fleshy body altogether inferiorly. The internal 

 flexor is feeble and conoid ; its tendon, thin and long, reaches the metacarpus of the 

 index. 



The perforatus of the Dog and Cat offers a long, -wide, and superficial body, 

 separated from the perforans by the oblique flexor of the metacarpus. Its tendon 

 passes outside the carpal sheath, and is divided into four branches, attached by their 

 inferior extremity to the second phalanx of the four principal digits. 



For the perforans, it is noted : 



1. That the radial portion of the muscle (the long flexor of the thumb in Man) com- 

 mences towards the superior extremity of the radius (fig. 125, c, 4). 



2. That the ulnar division is a semi-pen niform muscle, attached by the superior 

 extremities of its fibres to nearly the whole extent of the posterior face of the ulnar (fig. 

 125, c, 3). 



3. That the epitroohlean portion sends ofi', above the knee, a small particular 

 fasciculus terminating in a very thin tendon, which becomes lost in the fibrous arch of 

 the carpal sheath (fig, 125, c, 6). This small muscle represents the palmaris brevis of 

 Man. 



The terminal tendon divides into five branches, one for each digit (fig. 125, D, 4, &c.). 

 There have been already described in these animals : 



1. Two external radial muscles, only distinct at their terminal extremity, and con- 

 founded for the remainder of their extent. This is the anterior extensor of the meta- 

 carpus in Solipeds (fig. 125, a, 5, 6, 7). 



2. A long abductor of the thumb, which appears to be the representative of the 

 analogous muscle, and the short extensor of the same digit in Man. It is the oblique 

 extensor of the metacarpus in the Horse (fig. 125, a, 8). 



3. A common extensor of the digits ; the anterior extensor of the phalanges in the 

 Horse (fig. 125, A, 10). 



4. A proper extensor of the three external digits, the proper extensor of the little 

 finger in Man, or lateral extensor of the phalanges in the Horse (fig. 125, a, 10). 



5. A posterior ulnar, or external flexor of the metacarpus in the Horse (fig. 125, 

 A, 14). 



6. An anterior ulnar, or oblique flexor of the metacarpus in the Horse (fig. 125, 

 D, 6). 



7. A great palmar, corresponding to the internal flexor of the metacarpus in the 

 Horse (fig. 125, b, 8). 



8. A small palmar, a dependency of the deep flexor of the phalanges (fig. 125, c, 6). 



9. A flexor sublimis of tlie phalanges (fig. 125, D, 1). 



10. A deep flexor of the phalanges (fig'. 125, c, 5, D, 3). 



11. A long flexor of the thumb, united to the preceding muscle, the radial portion of 

 the perforans (fig. 125, c, 4). 



But in Carnivora there are five additional muscles, which are not generally found in 

 the other animals. These are : the proper extensor of the tlmmb and index, long 

 supinator, short supinator, round pronator, and the square pronator. A special descrip- 

 tion will be given of these. 



MUSCLES PEOPEB TO THE POEE-AKM OE CAENIVOBA, 



1. Proper Extensor of the Thumb and Index. (Fig. 125, a, 11 ; b, 3.) 

 Synonyms. — The extensor secundi internodii pollieis and extensor indieis of Man. 

 This is a vei-y small muscle, composed of a fleshy body and a tendon. The first is 

 thin and fusiform, and is situated under the lateral extensor ; it has its origin with the 

 oblique extensor of the metacarpus at the external side of the radius. The tendon 

 crosses the anterior aspect of the knee, enveloped by the synovial sheath of the common 

 extensor of the digits, under which it passes. It divides into two branches, one of 

 which goes to the thumb, the other to Ihe index.' 



2. Long Supinator. (Fig. 125, a, 12; o, 8.) 

 This muscle only exists in the rudimentary state in Carnivora. Its existence in (he 

 Dog has even been denied, but this is an error ; our researches" have demonstrated that 

 it is present, in a more or less evident manner, in all breeds. 



' In very powerful Horses, and more frequently in the Ox, we have met with traces 

 of this muscle in the form of a deep fasciculus situated in front of the lateral extensor. 



