62 Prof. A. Macalister on the Myology 



. Extensor carpi nlnaris arises from the outer condyle of the 

 humerus, and is inserted into the third metacarpal bone. In 

 the Armadillo it has an ulnar origin, and is inserted by the 

 intervention of a sesamoid bone into the base of the fifth meta- 

 carpal bone. In the Orycterope its insertion is into the fom-th 

 and fifth digits ; in the Anteaters, Two-toed and Tamandua, 

 its insertion is similar. 



Extensor digitorum communis is an exceedingly weak 

 muscle arising from the outer condyle of the humerus, and 

 inserted into the dorsal aponeurosis of the hand, dividing into 

 weak fascial slips traceable along the dorsum of each of the 

 two inner fingers ; the third seems deprived even of this sem- 

 blance of an extensor. In Choloe^ms didactyliis the tendon 

 goes to both digits ; the tendons of this muscle are much more 

 distinct in Orycteropus, Dasyinis^ and Myrmecopliaga^ and 

 seek an insertion usually into the last phalanges of the digits. 



Extensor ossis metacarpi pollicis arises from the middle of 

 the back of the ulna, and is inserted into the inner meta- 

 carpal bone at its base. This muscle does not seem to exist 

 in the Two-toed Anteater ; but it is present in M. jubata^ in 

 the Orycterope, and in the Armadilloes. 



Extensor indicis is a small muscle, and the only representa- 

 tive of the second series of extensors. It arises from the lower 

 extremity of the ulna, and is inserted into the base of the first 

 phalanx of the first digit. This muscle exists in the Orycterope, 

 in which animal it is inserted into the index and middle digits ; 

 in the Armadillo it goes, as in the dog, into index and pollex. 

 The extensors of the first and second poUicial internodes, to- 

 gether with those of the ring- and little finger, were completely 

 obsolete. 



The short muscles of the hand are : — Abductor primi digiti, 

 a short flat band passing from the scaphoid bone and annular 

 ligament to the first phalanx of the inner digit j on raising 

 this and the flexor tendons, I could see no ti-aces whatever of 

 palmar interossei. Extensor brevis digitorum manus, a small 

 muscle on the back of the hand, which seems to contain the 

 displaced germs of the dorsal interossei ; its tendon joins the 

 aponeurosis of the extensor digitorum longus, and is inserted 

 along with it. 



In the dissection of the pelvic limb, the abdominal muscles 

 displayed no particular features of interest. The external 

 oblique did not ascend as high as it is represented in the other 

 Edentates ; and the rectus was, as before mentioned, cut off 

 from its thoracic segment. 



Gluteus maximus, a small, superficial triangular muscle, 

 arises from the posterior border of the ilium, from the side of 



